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How do I solve 12x^2-89x-56 factor by grouping

User Ecc
by
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1 Answer

6 votes
use ac method

multiply 12 and -56
-672
now find what 2 factors of -672 add to -89
answer is -96 and 7

expand the middle term like that
12x²-96x+7x-56
group
(12x²-96x)+(7x-56)
factor
12x(x-8)+7(x-8)
undistribute the (x-8)
(x-8)(12x+7) is answer
User Benn Malengier
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7.8k points