Question

1. What is the factored form of 5x2 - 8x – 4?

a. (5x – 2)(x + 2)
b. (5x – 4)(x + 2)
c. (5x – 2)(x + 4)
d. (5x + 2)(x - 2)

Answer 1

(5x + 2) (x - 2 )

Explanation:

5x^2 - 8x – 4

(5x ) (x )

We need the middle to be -8 and 4 factors into 4*1 and 2*2

5*2 = 10 -2 = 8

(5x 2) (x 2 )

Now determine the signs

We need -8 so 5*2 must be negative and the 2*1 must be positive

(5x + 2) (x - 2 )