а) (x²+xy-y²)(x+y) б)(5x-2)(x²-x-1)

а) (x²+xy-y²)(x+y) =х³+х²у+х²у+ху²-у²х-у³=х³+2х²у-у³б)(5x-2)(x²-x-1)=5х³-5х²+5х-2х²+2х+2=5х³-7х²+7х+2