1) (2Х+1)(Х+4)=2х²+8х+х+4=2х²+9х+4
2) (2х+3)(5х-4)=10х²-8х+²5х-12=10х²-3х-12
3)(3х-2)(5х-4)=15х²-12х-10х+8=15х²-22х+8
4)(5а-3в)(4а-в)=20а²-5ав-12ав+3в²=20а²-17ав+3в²
5)(2т+3п)(2т-5п)=4т²-10тп+6тп-15п²=4т²-4тп-15п²
6)(3х+2у)(х-у)=3х²-3ху+2ух-2у²=3х²-ху-2у²
7)(5в-4с)(2в-2с)=10в²-10св-8св+8с²=10в²-18св+8с²=5в²-9св+4с²
8)(р-3q)(8p+5q)=8p²+5pq-24pq+25q²=8p²-19pq+25q²