x-y=3,xy=10,x^2+y^2=?
问题描述:
x-y=3,xy=10,x^2+y^2=?
答
x^2+y^2
=(x-y)^2+2xy
=3^2+2*10
=29
x-y=3,xy=10,x^2+y^2=?
x^2+y^2
=(x-y)^2+2xy
=3^2+2*10
=29