разложите на множители:
1. ab+ac-a
2. 4x^2-y^2+2x-y
ab+ac-a=a(b+c-1)
4x^2-y^2+2x-y=(2x-y)(2x+y)+1(2x-y)=(2x-y)(2x+y+1)
1. a(b+c-1) 2.(4x^2+2x)(-y^2-y)=2x(x+1)-y(y+1)=2x-y(x+1)(x+y)