2a+2b= 2(a+b)
ax+ay= a(x+y)
2ab+2ac= 2a(b+c)
abx+acy= a(bx+cy)
4ab+5ab= ab(4+5)=9ab
7a-7= 7(a-1)
4x-10y= 2(2x-5y)
a(x+y)+b(x+y)= (x+y)(a+b)
x(a+b)+2(a+b)= (a+b)(x+2)
ab+by+bc= b(a+y+c)
d(a+x)+c(a+x)= (a+x)(d+c)
4x+12y-12= 4(x+3y-3)
5ax+10ay+15ax= 5a(x+2y+3x)=5a(4x+2y)=10a(2x+y)
9(2x+y)+b(2x+y)=(2x+y)(9+b)
