Question

"Explain, in complete sentences, how you would completely factor 15x^2 – 25x – 60 by using the grouping method. How would you check your factors for accuracy?" If you could explain the grouping method, along with the meaning of the last sentence in the question, that'd rock.

Answer 1

trial and error

Answer 2

First you factor out the 5 from 15x^2 -25x-60, then it becomes 5(3x^2 -5-12).
There's only one combination for 3x^2, so in one of the term, it's 3x and the other x.
For -12, there's -3*4; -4*3; 2*-6; 6*-2; 12*-1 and -12*1.
So when you calculate 3 times -3 +4, you have -5, therefore the result is 5(3x+4)(x-3).
Hope this is clear enough to help.