Question

1) (а-2b)²-(a-b) (a+b)
2) (2a+b) (b-2a)-(a-b)²
3) (-2a-b)²-(a-b)²
4) -(2a-b)²-(a-b) (a+b)

Answer 1

1) = a^2-4ab+4a^2+b^2-a^2=5b^2-4ab
2)= 2ab-4a^2+b^2-2ab-a2+2ab-b^2=2ab-5a^2
3)= b^2+4ab+4a^2-b^2+2ab-a^2=6ab+3a^2
4) = -b^2+4ab-4a^2+b^2-a^2=4ab-5a^2