X+y=6 xy=4 xx+yy=
问题描述:
X+y=6 xy=4 xx+yy=
答
x²+y²=(x+y)²-2xy
=6²-2×4
=36-8
=28
X+y=6 xy=4 xx+yy=
x²+y²=(x+y)²-2xy
=6²-2×4
=36-8
=28