Question

50 points!!

What are the factors of the following polynomial: x^2−x−56
Do not include any spaces in your answer. Use parentheses to separate your factors. A sample answer might be (x+1)(x-4).

Answer 1

(x-8) (x+7)

Explanation:

x^2 -x-56

We want to factor this problem.

What two numbers multiply to negative 56 and add to -1

-8 *7 = -56

-8+7 = -1

We can use -8 and 7

(x-8) (x+7)

Check:

FOIL

first: x*x =x^2

outer: 7x

inner:-8x

last: -8*7 = -56

Add this together

x^2 +7x-8x -56 = x^2 -x-56