X(3x+2y)-(x+y)^2 при x=√7 , y=√10

Question

X(3x+2y)-(x+y)^2
при x=√7 , y=√10

Answer 1

X(3x+2y)-(x+y)^2=3х²+2ху-(х²+2ху+у²)=3х²+2ху-х²-2ху-у²=2х²-у²

при x=√7 , y=√10
2х²-у²=2*7-10=14-10=4