How do you factor $7x^2-10x-8$ ?

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Answer 1 · 2015-06-03T11:46:47

I will use a version of the AC Method...

$A=7$ , $B=10$ , $C=8$

Look for a pair of factors of $AC=56$ whose difference is $B=10$

The pair $B1=4$ , $B2=14$ works.

Then for each of the pairs $(A, B1)$ and $(A, B2)$ divide by the HCF (highest common factor) to find the coefficients of a factor of the quadratic...

$(A, B1) = (7, 4) -> (7, 4) -> (7x+4)$
$(A, B2) = (7, 14) -> (1, 2) -> (x-2)$

So $7x^2-10x-8 = (7x+4)(x-2)$

How do you factor 7x^2-10x-87x^2-10x-8?