Respuesta :

Answer:

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).