已知x^2+y^2=4,x-y=1,试求:(x+y)^2,x^2y^2的值.

大哥大姐,打扰一下,已知x^2+y^2=4,x-y=1,试求:(x+y)^2,x^2y^2的值.
最新回答
落花终究无情ゞ

2025-03-27 01:09:54

(x-y)²=x²+y²-2xy=4-2xy=1 2xy=3
(x+y)^2=x²+y²+2xy=4+3=7x^2y^2=(xy)²=4分之9
追答
(x-y)²=x²+y²-2xy=4-2xy=1  2xy=3 
(x+y)^2=x²+y²+2xy=4+3=7x^2y^2=(xy)²=4分之9