1) a-b+2c(a-b) 2) by+3b+2cy+6c 3) kl-5l-k+5 4) 3ab-2ac+4cd-6bd 5) y2-2by+6b-3y y2 это y во 2 степени

1) a-b+2c(a-b) = (a-b)(1+2c)
2) by+3b+2cy+6c = (by+2cy)+(3b+6c) = y(b+2c)+3(b+2c) = (b+2c)(y+3)
3) kl-5l-k+5 = k(l-1)-5(l-1) = (l-1)(k-5)
4) 3ab-2ac+4cd-6bd = (-2ac+4cd)+(3ab-6bd) = 2c(2d-a)-3b(2d-a)=(2d-a)(2c-3b)
5) y^2-2by+6b-3y = y(y-2b)+3(2b-y)= (y-2b)(y-3)