Factor by grouping (write out all of the factoring)

3x^2+18x-6x-36

3 (x + 6) (x - 2)

Step-by-step explanation:

Given

3x² + 18x - 6x - 36 ← factor out 3 from each term

= 3 (x² + 6x - 2x - 12) (factor the first/second and third/fourth terms)

= 3 (x (x + 6) - 2 (x + 6)) ← factor out (x + 6) from each term

= 3 (x + 6) (x - 2)