Question

Factor completely: 18x2 - 21x - 15


3(6x + 1)(x - 5)

3(2x - 1)(3x + 5)

3(2x + 1)(3x - 5)

3(2x - 5)(3x + 1)

Answer 1

First factor 3 out
\[
18 x^2 - 21 x - 15= 3(6x^2 -7x -5)
\]

Answer 2

\[

18 x^2-21 x-15=3 (2 x+ ?) (3 x-?)

\]

Answer 3

\[
18 x^2-21 x-15=3 (2 x+1) (3 x-5)
\]

Answer 4

Thanks for explaining it, I was just about to type that answer!

Answer 5

That means you understood what was involved. Great.