问题:
已知:x+y=4,xy=2,则x 2+y 2=
A.10
B.12
C.16
D.18
已知:x+y=4,xy=2,则x 2+y 2=
A.10
B.12
C.16
D.18
A.10
B.12
C.16
D.18
参考答案: