Solving Quadratic Equations using Quadratic Formula

MATH TEACHER GON
27 Sept 202306:26

Summary

TLDRIn this educational video, the host, Caregon, introduces viewers to solving quadratic equations using the quadratic formula. The script walks through the process of solving the equation 2x^2 - 4x - 30 = 0 step by step, emphasizing the importance of expressing the equation in standard form to identify coefficients a, b, and c. The video demonstrates the formula x = (-b ± sqrt(b^2 - 4ac)) / 2a and simplifies it to find the roots, which are x = 5 and x = -3. The host encourages viewers to learn and apply this method, promoting engagement with the content.

Takeaways

  • 📚 The video explains how to solve quadratic equations using the quadratic formula.
  • ✏️ The quadratic formula is used as an alternative method to factoring, completing the square, and square roots.
  • 🧮 The formula for solving quadratic equations is X = (-B ± √(B² - 4AC)) / 2A.
  • 🔍 Before applying the formula, the equation must be in standard form, where A, B, and C are identified.
  • ➗ In the example, 2x² - 4x - 30 = 0, the values of A, B, and C are 2, -4, and -30 respectively.
  • 🔢 The discriminant (B² - 4AC) is calculated as 16 + 240, giving a total of 256.
  • 🟢 Since the square root of 256 is 16, the equation becomes X = (4 ± 16) / 4.
  • ➕ The first solution (X₁) is calculated as (4 + 16) / 4 = 5.
  • ➖ The second solution (X₂) is calculated as (4 - 16) / 4 = -3.
  • ✅ The final solutions for the quadratic equation are X = 5 and X = -3.

Q & A

  • What is the main topic of the video?

    -The main topic of the video is solving quadratic equations using the quadratic formula.

  • What are the alternative methods mentioned for solving quadratic equations?

    -The alternative methods mentioned are factoring, completing the square, and using square roots.

  • What is the quadratic formula used to solve quadratic equations?

    -The quadratic formula is x = (-b ± √(b^2 - 4ac)) / 2a.

  • What is the first step in using the quadratic formula?

    -The first step is to express the equation in standard form to identify the values of a, b, and c.

  • What are the values of a, b, and c in the example equation 2x^2 - 4x - 30 = 0?

    -In the example equation, a is 2, b is -4, and c is -30.

  • How do you calculate the discriminant in the quadratic formula?

    -The discriminant is calculated as b^2 - 4ac.

  • What is the discriminant for the example equation 2x^2 - 4x - 30 = 0?

    -The discriminant is (-4)^2 - 4(2)(-30) = 16 + 240 = 256.

  • What are the two solutions for the example equation using the quadratic formula?

    -The two solutions are x = 5 and x = -3.

  • What does the plus-minus symbol in the quadratic formula represent?

    -The plus-minus symbol indicates that there are two possible solutions, one using addition and the other using subtraction.

  • How does the video encourage viewers to engage with the content?

    -The video encourages viewers to like and subscribe for updates on the latest uploads.

Outlines

00:00

📘 Introduction to Solving Quadratic Equations

This paragraph introduces the topic of solving quadratic equations using the quadratic formula. The speaker, identified as 'the caregon,' presents this method as an alternative to other common techniques such as square roots, completing the square, and factoring. The focus is on the quadratic formula, which is used to solve the equation 2x^2 - 4x - 30 = 0. The speaker explains the process of expressing the equation in standard form to identify the coefficients a, b, and c, which are crucial for applying the formula. The values for a, b, and c are identified as 2, -4, and -30, respectively. The formula is then applied step by step, with the speaker detailing each calculation, including the simplification of the square root and the final solution for x.

05:01

🔢 Solving the Quadratic Equation Step by Step

In this paragraph, the speaker continues the explanation of solving the quadratic equation 2x^2 - 4x - 30 = 0 using the quadratic formula. The process involves calculating the discriminant (B^2 - 4AC) and then solving for x by taking the square root of the discriminant and dividing by 2a. The speaker simplifies the discriminant to 256 and then takes the square root to find the values of x. Two solutions are presented: x = 5 and x = -3. The speaker emphasizes the importance of understanding each step in the process to successfully solve quadratic equations. The paragraph concludes with a call to action for viewers to like and subscribe to the channel for more educational content.

Mindmap

Keywords

💡Quadratic Equations

Quadratic equations are polynomial equations of degree two, meaning they have the highest power of 2 for the variable. They are commonly expressed in the form ax^2 + bx + c = 0, where a, b, and c are constants. In the video, the speaker focuses on solving quadratic equations using the quadratic formula, which is a method to find the roots of such equations. The example given in the script is 2x^2 - 4x - 30 = 0, which is a typical quadratic equation.

💡Quadratic Formula

The quadratic formula is a standard algebraic method for solving quadratic equations. It is expressed as x = [-b ± sqrt(b^2 - 4ac)] / (2a). This formula allows for finding the roots of any quadratic equation, regardless of whether they are real or complex. The video script demonstrates the application of this formula to the equation 2x^2 - 4x - 30 = 0, showing each step of the calculation to derive the values of x.

💡Standard Form

Standard form in the context of quadratic equations refers to the arrangement of the equation in the form ax^2 + bx + c = 0, with the terms ordered by descending powers of the variable x. The video emphasizes the importance of expressing the equation in standard form before applying the quadratic formula, as it helps in identifying the coefficients a, b, and c, which are essential for the formula.

💡Coefficients

In the context of the video, coefficients refer to the numerical factors of the terms in a quadratic equation. Specifically, 'a' is the coefficient of x^2, 'b' is the coefficient of x, and 'c' is the constant term. The speaker identifies these coefficients from the given equation (a = 2, b = -4, c = -30) and uses them in the quadratic formula to find the solutions.

💡Solving

Solving, in algebra, means finding the values of the variable that make the equation true. In the video, the process of solving involves applying the quadratic formula to the equation 2x^2 - 4x - 30 = 0 to find the values of x. The script outlines each step, from identifying coefficients to simplifying the radical and calculating the roots.

💡Roots

Roots of a quadratic equation are the values of the variable that satisfy the equation, making it true. The video script demonstrates finding the roots of the equation 2x^2 - 4x - 30 = 0 by using the quadratic formula. The roots are the solutions to the equation, and in this case, the video finds two roots: x = 5 and x = -3.

💡Square Root

A square root is a value that, when multiplied by itself, gives the original number. In the quadratic formula, the square root is taken of the discriminant (b^2 - 4ac). The video script shows the calculation of the square root in the context of the quadratic formula, where the discriminant is 16 + 240, leading to the square root of 256, which simplifies to 16.

💡Discriminant

The discriminant of a quadratic equation, denoted as b^2 - 4ac, determines the nature of the roots. If it's positive, the equation has two distinct real roots; if zero, one real root (or two identical real roots); and if negative, two complex roots. In the video, the discriminant is calculated as part of the quadratic formula application, leading to the determination of real roots.

💡Simplification

Simplification in mathematics refers to making an expression easier to understand or calculate by reducing it to its simplest form. The video script includes simplification of the quadratic formula's result, where the radical part and the coefficients are simplified to find the roots of the equation. This process is crucial for obtaining the final solutions for x.

💡Like and Subscribe

These terms are common in the context of video content platforms like YouTube, where creators encourage viewers to 'like' their videos and 'subscribe' to their channels for updates on new content. In the video script, the speaker ends with a call to action for viewers to like and subscribe, which is a standard practice to grow an audience and increase engagement.

Highlights

Introduction to solving quadratic equations using the quadratic formula.

Alternative methods for solving quadratic equations include factoring, completing the square, and using square roots.

Quadratic formula is presented as a method to solve quadratic equations.

Equation 2x^2 - 4x - 30 = 0 is used as an example to demonstrate the quadratic formula.

Explanation of expressing the equation in standard form to identify coefficients a, b, and c.

Identification of the values of a (2), b (-4), and c (-30) for the given equation.

Step-by-step application of the quadratic formula to find the values of x.

Calculation of the discriminant (b^2 - 4ac) and its significance in the quadratic formula.

Simplification of the square root term in the quadratic formula.

Derivation of the two possible solutions for x from the quadratic formula.

Solution x1 = 5 is obtained from the positive square root.

Solution x2 = -3 is obtained from the negative square root.

Final solutions to the equation are x = 5 and x = -3.

Encouragement for viewers to learn from the video and apply the quadratic formula.

Call to action for viewers to like and subscribe for updates on latest uploads.

Conclusion and farewell from the presenter.

Transcripts

play00:01

hi guys it's me the caregon in today's

play00:03

video we will talk about solving

play00:05

quadratic Creations using quadratic

play00:08

formula

play00:09

so without further ado

play00:11

let's do this topic

play00:13

this topic is an alternative method on

play00:16

how to solve quadratic equations we have

play00:18

destruction the square roots completing

play00:21

the square and factoring and in capacity

play00:24

that working migration stay on you can

play00:26

use the quadratic formula to solve

play00:27

quadratic creations

play00:29

now

play00:30

what we have here is 2x squared minus 4X

play00:34

minus 30 is equal to zero and we will

play00:37

solve this using the formula X is equal

play00:40

to negative B positive negative square

play00:42

root of B squared minus 4AC over to a

play00:46

what you need to secure here is first

play00:48

you need to express your equation in

play00:52

standard form and then eventually you

play00:55

can get the values of

play00:57

a

play00:58

B and C because

play01:01

to use this formula in this equation

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what is the value of a the value of a is

play01:07

two

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the value of B is not 4 that is negative

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4.

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the value of C is negative

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30. now after identifying or determining

play01:22

the values of a b and c we can use the

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formula we have here x

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is equal to negative

play01:32

your B is negative also so you can

play01:35

enclose it by parenthesis you have

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negative

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four

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then you have positive negative

play01:42

then after that square root off

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B squared this is negative 4 guys

play01:48

you have to include it by parenthesis

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negative four

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raised to the second power

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and then extend that into

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we have four in your formula minus four

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then guys for a and c and 4 you need to

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express it as in multiplication your a

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is two so four times two

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times your C is negative 30.

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over

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2

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times your a is to

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radical

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so um

play02:37

in this case you have your ex

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is equal to negative times negative is

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positive so it will become Sim

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4

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then you have your positive negative

play02:48

let's simplify the radical part

play02:51

negative 4 squared is 16.

play02:56

then this one negative 4 times 2 times

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negative 30.

play03:03

you have negative four times two

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that is negative eight so you have

play03:08

negative eight then you will multiply

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negative eight again this negative eight

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it came from the product of negative

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four and two negative four times two is

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negative eight then you will multiply it

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this negative eight by negative 30.

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negative times negative is positive so

play03:27

this is Plus

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then you have eight times thirty again

play03:31

eight times thirty that is two hundred

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forty

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over

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2 times 2 which is equal to 4.

play03:44

we can we cannot cancel out four Hindi

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question

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next is we need to simplify this radical

play03:53

16 plus 240 that is 256. so what we have

play03:58

now is X

play04:00

is equal to four

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positive negative square root of 256

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over

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4.

play04:10

and this square of 256 this number is a

play04:14

perfect square

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we can extract it the square root of 256

play04:18

is 16.

play04:20

so what we have here is X

play04:22

is equal to 4.

play04:24

positive negative 16 over

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4. when you are done simplifying the

play04:30

radical part

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we can now solve for the values of X

play04:34

let's go here let's use this space

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let's start with x sub 1.

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for the x sub 1

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we will use four

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then this is positive negative positive

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Muna we have plus 16 over

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four

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simplify this part you have

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4 plus 16 which is 20.

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over 4 and 20 divided by 4 that is equal

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to

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5. and as you can see

play05:08

this is the first

play05:11

solution of the given equation

play05:13

the value of x is 5. now let's go with

play05:16

the x sub 2 or the second root

play05:19

x sub 2.

play05:21

for the x sub 2 you have four and we are

play05:24

done using the positive 16 or plus 16

play05:26

minamine is minus

play05:29

16 over

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4. simplify

play05:33

4 minus 16

play05:35

you have your

play05:36

negative 12 over 4.

play05:40

then divide this

play05:41

negative 12 divided by 4 is negative

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three so as you can see this is now the

play05:48

second value of x we have X is equal to

play05:51

negative three

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now for this given equation the

play05:55

solutions are 5 and negative three now

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guys

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I hope you learned something from this

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video on how to use the quadratic

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formula in solving quadratic equations

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now if you're new to my page or Channel

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please don't forget to like And

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subscribe button

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for you to be updated latest uploads

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again

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it's literature gone

play06:22

bye

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