3m^2-17m-56=0 Algebra help - Factoring

Im not sure what I'm supposed to do here:
3m^2-17m-56=0
Usually I would be able to divide the first number in with the rest but I can't do that here, can anyone of you explain please?

First B does not have the right answer. Here it is:
(3m+7) (m-8) = 0
3m = -7, so m = -(7/3), or - 2 and 1/3 , and m =8

This equation is in ax^2+bx+c form so you can solve the equation using the AC method.
Multiply A by C.
m^2-17m-168
Now factor using abc
(m-24)(m+7)
Reintroduce the value of a (3)
(3m-24)(3m+7)
Divide by the value of a (3)
(m-8)(3m+7)

(m-8)(3m+7) is your answer.

You still can. It's just a little more difficult than solving a quadratic without a numeric value on the 2nd degree term.

(3m - 7)(m + 8)

3m^2 - 17m - 56 = 0
(3m + 7)(m - 8) = 0
Solutions:
m = -7/3
m = 8