1. ac^2-c^2+ac-c=(ac^2-c^2)+(ac-c)=c^2(a-1)+c(a-1)=(a-1)(c^2+c)
2.x^5+x^4-x^3-x^2+6x-6=(x^5+x^4)+(-x^3-x^2)+(6x-6)=x^4(x+1)-x^2(x+1)+6(x-1)=(x+1)(x^4-x^2-6)
1)=ac(ac-c+1-1)
2)=6x(x^4+x^3-x^2-x+1-1)
