1) а*b*c+a*b= abc+ab= ab (c+1)
2)a*b*c - 64*c= abc-64c= c (ab-64)
3)23*a*b+2*a-3*2a=23ab+2a-6a=2a (11,5b+1-3)=11,5b-2
4)42*x*y+11*x=42xy+11x=x (42y+11)
5)6xy+3y+36=3 (2xy+y+12)
6)(7xy-7x)+(55xy-5x)=7x (y-1)+5x (11y-1)
7)(8x^2+4x)+1=4x (2x+1)+1
8)5x^5-10x^3+35x^6=5x^3 (x^2-2+7x^3)