How do you factor #18x^2+3x-10# by grouping?

1 Answer
May 11, 2016

Answer:

#18x^2+3x-10=(3x-2)(6x+5)#

Explanation:

You need to find how to split the middle term first.

Use an AC Method:

Look for a pair of factors of #AC=18*10=180# which differ by #B=3#.

The pair #15, 12# works in that #15xx12=180# and #15-12=3#.

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

#18x^2+3x-10#

#=18x^2+15x-12x-10#

#=(18x^2+15x)-(12x+10)#

#=3x(6x+5)-2(6x+5)#

#=(3x-2)(6x+5)#