How do you factor completely: #2x^2 - 6x - 56#?

1 Answer
George C.
Jul 18, 2015

Separate out the scalar factor #2# then find pair of numbers #4# and #7# whose product is #28# and difference #3#, hence...

#2x^2-6x-56 = 2(x-7)(x+4)#

Explanation:

#2x^2-6x-56 = 2(x^2-3x-28)#

To factor #x^2-3x-28#, find a pair of numbers whose product is #28# and whose difference is #3#. The pair #7#, #4# works.

So #x^2-3x-28 = (x-7)(x+4)#

and

#2x^2-6x-56 = 2(x-7)(x+4)#

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