Question

Factorise 4(a+b)^2-9(a-b)^2

Answer 1

4(a+b)^2-9(a-b)^2

4(a^2+2ab+b^2)-9(a^2+2ab-b^2

4(a^2+8ab+4b^2-9a^2-18ab-19b^2

4(a^2-9a^2+8ab-18ab+4b^2+9b^2

(5a-b) (5b-a)