(a+b)^2-(a+b)(a-b)= x(x-y)^2-y(y-x)^2= n(m-n)^2-(n-m^3)= a(a-c)^2-c(a-c)(c-a)=
1)a²+2ab+b²-a²+b²=2ab+2b²=2b(a+b) 2)x³-2x²y+xy²-y³+2xy²-x²y=x³-3x²y+3xy²-y³=(x-y)³ 4)a³-2a²c+ac²+c³-a²c=a³-3a²c+ac²+c³