Tính: a(a - b) + b(a - b); a(a ^ 2 - 2ab + b ^ 2) - b(a ^ 2 - 2ab + b ^ 2)

e) a(a - b) + b(a - b)
f) a(a ^ 2 - 2ab + b ^ 2) - b(a ^ 2 - 2ab + b ^ 2)