Question

I need help i don't how to do this can some one help me by walking me by step by step?

[8.03] Identify the factors of x2 − 8x − 20.

(x + 4)(x − 5)

(x + 5)(x − 4)

(x − 10)(x + 2)

(x − 2)(x + 10)

Answer 1

you need 2 numbers whose product is -20 and whose sum is -8

Answer 2

try some factors of -20 and see if you can get -8 when you add them

Answer 3

what about -10 and 2 ?

Answer 4

you get -8

Answer 5

-10 * 2 = -20
and -10 + 2 = -8

Answer 6

so the factors are

(x + 2)(x - 10)