Question

9(a+b)²-12(a²-b²)+4(a-b)² please solve

Answer 1

In the first one 9(a+b)^2 =9(a^2+2ab+b^2) =9a^2+18ab+9b^2  In the second one -12(a^2-b^2) = -12((a+b)(a-b)) = -12(2a) =-24a  In the third one  4(a-b)^2 =4(a^2+b^2-2ab) =4a^2+4b^2-8ab  Summing like terms 9a^2+4a^2+9b^2+4b^2+18ab-8ab-24a =13a^2+13b^2+10ab-24a