Which is the completely factored form of 3xsquared

-12x-15?

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

Step-by-step explanation:

3x^2 - 12x - 15

Dividing through by 3:

= 3 (x^2 - 4x - 5)

We need 2 numbers whose sum is - 4 and whose product = - 5. That is - 5 and + 1, so the factors are:

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