x-y=3,xy=2,则(x+y)^2=_______。
告诉我,谢谢
参考答案:x-y=3
(x-y)^2=9
x^2-2xy+y^2=9
x^2-2*2+y^2=9
x^2+y^2=13
(x+y)^2
=x^2+2xy+y^2
=x^2+y^2+2xy
=13+2*2
=17
告诉我,谢谢
参考答案:x-y=3
(x-y)^2=9
x^2-2xy+y^2=9
x^2-2*2+y^2=9
x^2+y^2=13
(x+y)^2
=x^2+2xy+y^2
=x^2+y^2+2xy
=13+2*2
=17