a^3+2a^2b+ab^2+a+b = a(a^2+2ab+b^2) + (a+b) = a(a+b)^2 + (a+b) = (a+b)(a^2+2ab+b) = (a+b)(a+b)^2 = (a+b)^3
a^3+2a^2b+ab^2+a+b = a(a^2+2ab+b^2) + (a+b) = a(a+b)^2 + (a+b) = (a+b)(a^2+2ab+b) = (a+b)(a+b)^2 = (a+b)^3