so factor use reverse distributiver property ab+ac=a(b+c) or ab-ac=a(b-c) so we need to find a find the common factors of the variables 4=2 times 2 8=2 times 2 times 2 common is 2 times 2=4 so 4 is a factor of both so 4x-8=(4)x-(4)2=(4)(x-2) 4(x-2) is the answer
