Question

упростите выражение (3х-7у)(2х+3у)-(4х-5у)(3х+у)

Answer 1

6х^2+9ху-14ху-21у^2-(12х^2+4ху-15ху-5у^2)=
6х^2+9ху-14ху-21у^2-12х^2-4ху+15ху+5у^2=-6х^2+11ху-16у^2.