McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
5. Solving Quadratic Equations by Using the Quadratic Formula
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Exercise 23 Page 137

Make sure you write all the terms on the left-hand side of the equation and simplify as much as possible before using the Quadratic Formula.

0.5, - 2

Practice makes perfect
We will use the Quadratic Formula to solve the given quadratic equation. ax^2+ bx+ c=0 ⇕ x=- b± sqrt(b^2-4 a c)/2 a Let's start by rewriting the equation so all of the terms are on the left-hand side and then simplify as much as possible.
8x^2 + 12x = 8
8x^2 + 12x - 8 = 0
4(2x^2 + 3x - 2) = 0
2x^2 + 3x - 2 = 0
Now, we can identify the values of a, b, and c. 2x^2 + 3x - 2 = 0 ⇕ 2x^2+ 3x+( - 2)=0 We see that a= 2, b= 3, and c= - 2. Let's substitute these values into the Quadratic Formula.
x=- b±sqrt(b^2-4ac)/2a
x=- 3±sqrt(3^2-4( 2)( - 2))/2( 2)
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Solve for x and Simplify
x=- 3±sqrt(9-4(2)(- 2))/2(2)
x=- 3±sqrt(9-8(- 2))/4
x=- 3±sqrt(9+16)/4
x=- 3±sqrt(25)/4
x=- 3 ± 5/4
The solutions for this equation are x= - 3± 54. Let's separate them into the positive and negative cases.
x=- 3 ± 5/4
x_1=- 3 + 5/4 x_2=- 3 - 5/4
x_1=2/4 x_2=- 8/4
x_1=0.5 x_2=- 2

Using the Quadratic Formula, we found that the solutions of the given equation are x_1=0.5 and x_2=- 2.