已知x-y=-3,xy=5,求x^2+y^2的值
问题描述:
已知x-y=-3,xy=5,求x^2+y^2的值
答
x^2+y^2
=(x-y)^2+2xy
=9+10
=19
已知x-y=-3,xy=5,求x^2+y^2的值
x^2+y^2
=(x-y)^2+2xy
=9+10
=19