Solved on Oct 24, 2023

Find the roots of the quadratic equation 2x2x28=02x^2 - x - 28 = 0 by factoring.

STEP 1

Assumptions1. The quadratic function is f(x)=xx28f(x)=x^-x-28 . We are finding the zeros by factoring

STEP 2

To find the zeros of the quadratic function, we first need to factorize the quadratic equation. The general form of a quadratic equation is ax2+bx+c=0ax^2 + bx + c =0. We need to find two numbers that multiply to aca \cdot c (product) and add up to bb (sum).

STEP 3

In our case, a=2a =2, b=1b = -1 and c=28c = -28. So, we need to find two numbers that multiply to 228=562 \cdot -28 = -56 and add up to 1-1.

STEP 4

The two numbers that satisfy these conditions are 8-8 and 77 because 87=56-8 \cdot7 = -56 and 8+7=1-8 +7 = -1.

STEP 5

Now, we rewrite the middle term of the quadratic equation as the sum of the terms 8x-8x and 7x7x.
f(x)=2x28x+7x28f(x) =2x^2 -8x +7x -28

STEP 6

We factor by grouping. First, group the first two terms together and the last two terms together in the equation.
f(x)=(2x28x)+(x28)f(x) = (2x^2 -8x) + (x -28)

STEP 7

Factor out the greatest common factor (GCF) from each group.
f(x)=2x(x4)+7(x4)f(x) =2x(x -4) +7(x -4)

STEP 8

Now, you can see that (x4)(x -4) is a common factor. Factor this out.
f(x)=(2x+7)(x4)f(x) = (2x +7)(x -4)

STEP 9

Setting this equation equal to zero gives the solutions to the equation, which are the zeros of the function.
2x+7=orx4=2x +7 = \quad or \quad x -4 =

STEP 10

olve these two equations to find the zeros.
For 2x+7=02x +7 =0, subtract 77 from both sides and then divide by 22 to get x=72x = -\frac{7}{2}.
For x4=0x -4 =0, add 44 to both sides to get x=4x =4.
So, the zeros of the function f(x)=2x2x28f(x)=2x^2-x-28 are x=72x = -\frac{7}{2} and x=4x =4.

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