Question

Using complete sentences, explain how to completely factor 2x2 − 8x − 42.

Answer 1

take out 2 as a factor of every term

\[2(x^2 -4x - 21)\]

next find the factors of -21 that add to - 4 (hint the larger factor is negative)


1 and - 21 1 - 21 = 20

3 and - 7 3 - 7 = -4

the factors to use are 3 and - 7

then its

\[2x^2 - 8x - 42 = 2(x-7)(x+3)\]

Answer 2

thanks