11! разложите на множители: a^2-b^2+a+b a^3+a^2b-ab^2-b^3 xc-yc-x^2+2xy-y^2

1) a^2 - b^2 + a +b = (a-b)(a+b) +a+b = (a+b)(a-b+1)
2) a^3+a^2b -ab^2 - b^3=(a-b)^3 + 4a^2b - 4ab^2 = (a-b)^3 +4ab(a-b)=(a-b)((a-b)^2-4ab)
3) xc-yc-x^2+2xy-y^2 = c(x-y) -(x-y)^2 = (x-y)(c-(x-y))