How do you factor #12x^2 - 5x - 2# by grouping?

1 Answer
EZ as pi
Jun 12, 2016

#(3x - 2)(4x + 1)#

Explanation:

First multiply #12 xx 2 = 24#
Find factors of 24 which differ by 5. These are 8 and 3.

This tells you how to rewrite the middle term (-5)

#12x^2 -8x +3x -2#

#(12x^2 - 8x) + (3x - 2) " form pairs"#

#4x(3x - 2) + (3x - 2) " common factor"#

#(3x - 2)(4x + 1) " common bracket"#

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