Question

упростить (x+y)(x-y)-(x^2+3y^2)

Answer 1

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

Answer 2

х^2+ху+ху-у^2-х^2-3у^2=2ху-4у^2