Question

1.Упростите выражение:
a)(3a-b)(a-7b)+a(22b-2a)
б)3c(4c-5)-(c-8)(c-7)
в)(y-5)во 2 степени-(5-у)(5+у)

Answer 1

(3a-b)(a-7b)+a(22b-2a)=3a²-21ab-ab+7b²+22ab-2a²=a²+7b²

3c(4c-5)-(c-8)(c-7)=12c²-15c-(c²-7c-8c+56)=12c²-15c-(c²-15c+56)=
=12c²-15c-c²+15c-56=11c²-56

(y-5)²-(5-у)(5+у)=y²-10y+25-(25-y²)=y²-10y+25-25+y²=2y²-10y