How do you factor #4x^3+2x^2-2x-1#?
1 Answer
Sep 1, 2016
Explanation:
Notice that the ratio of the first and second terms is the same as that of the third and fourth terms. So this cubic will factor by grouping:
#4x^3+2x^2-2x-1#
#=(4x^3+2x^2)-(2x+1)#
#=2x^2(2x+1)-1(2x+1)#
#=(2x^2-1)(2x+1)#
#=((sqrt(2)x)^2-1^2)(2x+1)#
#=(sqrt(2)x-1)(sqrt(2)x+1)(2x+1)#
