-24ав-(4а-3в)^2=
=-24ав-(16а^2-24ав+9в^2)=
=-24ав-16а^2+24ав-9в^2=
=-16а^2-9в^2=-16×8-9×3=
=-155
сократить дробь
=(х^2-у^2)^2/(х-у)^2 ÷
÷(у^2-х^2)/х^2у^2=
=(х^2-у^2)^2×х^2у^2/(х-у)^2(у^2-х^2)=(х^2-у^2)×х^2у^2/(х-у)^2=
=(х-у)(х+у)×х^2у^2/(х-у)^2=
=х^2у^2(х+у)/(х-у)