SOLUTION: how do I factor completely: 4a^2 -4a -48

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Question 283379: how do I factor completely:
4a^2 -4a -48
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
right away you can see that you can factor 4
4*(a^2-a-12)
now we have 1 and 12
so we need factors of twelve with a difference of one
1 12 11
2 6 4
3 4 1
4 3 1
we are repeating and the only match is 3 and 4
the larger number must be negative
(a-4)*(a+3)
so now we have 4*(a-4)*(a+3)