Автор - Angelin43
(3xy² + 5x²y² - 7xy + 7 + 11) + (- 2xy² + x²y² + 2xy + y - 2) =
= 3xy² + 5x²y² - 7xy + 18 - 2xy² + x²y² +2xy + y - 2 =
= 6x²y² + xy² - 5xy + y + 16
(3xy²+5x²y²-7xy+7+11) +(-2xy²+x²y²+2xy+y-2) =
= 3xy²+5x²y²-7xy+18 -2xy²+x²y²+2xy +y-2 =
= 6x²y² +xy²-5xy+y+16