题目内容
| 已知(x+y)2=1,(x-y)2=49, (1)x2+y2 =( ) A.22 B.25 C.28 D.30 (2)xy=( ) A.-12 B.-10 C.12 D.15 |
试题答案
B,A
相关题目
题目内容
| 已知(x+y)2=1,(x-y)2=49, (1)x2+y2 =( ) A.22 B.25 C.28 D.30 (2)xy=( ) A.-12 B.-10 C.12 D.15 |
试题答案
B,A