How do you factor the expression #20x^2 + 13x + 2#?

1 Answer
George C.
Apr 26, 2016

#20x^2+13x+2=(4x+1)(5x+2)#

Explanation:

Use an AC method:

Find a pair of factors of #AC = 20*2 = 40# with sum #B=13#.

The pair #8, 5# works in that #8xx5=40# and #8+5 = 13#

Use this pair to split the middle term and factor by grouping:

#20x^2+13x+2#

#=20x^2+8x+5x+2#

#=(20x^2+8x)+(5x+2)#

#=4x(5x+2)+1(5x+2)#

#=(4x+1)(5x+2)#

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