Factor completely.

3w^2+15w-72

To factor completely, we first need to find two numbers that multiply to -72 and add up to 15. The two numbers that satisfy these conditions are 24 and -3.

Therefore, we can rewrite the expression as:
3w^2 + 24w - 9w - 72

Next, factor by grouping:
3w(w + 8) - 9(w + 8)

Now, we can factor out the common factor of (w + 8):
(w + 8)(3w - 9)

Finally, we can simplify the expression:
(w + 8)(3w - 9) = (w + 8)(3(w - 3)) = 3(w + 8)(w - 3)

So, the expression 3w^2 + 15w - 72 can be factored completely as 3(w + 8)(w - 3).