Question

(Зх + 4у)^2- (4х + 3у)(4х-3у)-25у^2

Answer 1

$(3x+4y)^2-(4x+3y)(4x-3y)-25y^2= \ 9x^2+24xy+16y^2-(16x^2-9y^2)-25y^2= \ 9x^2-16x^2+16y^2+9y^2-25y^2+24xy=-7x^2+24xy=-x(7x+24y)$