Question

разложите на множители (3х+у)в квадрате-(х-3у)в квадрате

Answer 1

$(3x+y)^2-(x-3y)^2=(3x+y+x-3y)(3x+y-x+3y)=$$(4x-2y)(2x+4y)=4(2x-y)(x+2y)$

Answer 2

(3x+y)^2- (x-3y)^2= (3x+y-x+3y) (3x+y+x-3y)= (2x+4y) (4x-2y)= 2(x+2y)*2 (2x-y) = 4 (x+2y) (2x-y)