Core Connections Integrated II, 2015
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Core Connections Integrated II, 2015 View details
1. Section 7.1
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Exercise 28 Page 382

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.

Solution: x= 13, x=- 6
Does the solution match? Yes.

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 rearranging the equation so all of the terms are on the left-hand side of the equation. 0=3x^2+17x-6 ⇕ 3x^2+17x-6=0 Now we can identify the values of a, b, and c. 3x^2+17x-6=0 ⇕ 3x^2+ 17x+( - 6)=0 We see that a= 3, b= 17, and c= - 6. Let's substitute these values into the Quadratic Formula.
x=- b±sqrt(b^2-4ac)/2a
x=- 17±sqrt(17^2-4( 3)( - 6))/2( 3)
â–Ľ
Solve for x and Simplify
x=- 17±sqrt(289-4(3)(- 6))/2(3)
x=- 17±sqrt(289-12(- 6))/6
x=- 17±sqrt(289+72)/6
x=- 17±sqrt(361)/6
x=- 17± 19/6
The solutions for this equation are x= - 17± 196. Let's separate them into the positive and negative cases.
x=- 17± 19/6
x_1=- 17+19/6 x_2=- 17-19/6
x_1=2/6 x_2=- 36/6
x_1=1/3 x_2=- 6

Using the Quadratic Formula, we found that the solutions are x_1= 13 and x_2=- 6. Notice that those are the same solutions as obtained in Part B of the previous exercise, where we solved the equation by factoring and then using Zero Product Property. Both methods are equally good, so they give the same solutions.