问题
解答题
若x=
|
答案
∵x=
=1
-23
=-
+23 (
-2)(3
+2)3
-2,y=3
=1
+23
=2-
-23 (
+2)(3
-2)3
,3
∴x+y=-2
,xy=-1,3
∴原式=
=x2+xy+y2 x+y
=-(x+y)2-xy x+y
.13 3 6
若x=
|
∵x=
=1
-23
=-
+23 (
-2)(3
+2)3
-2,y=3
=1
+23
=2-
-23 (
+2)(3
-2)3
,3
∴x+y=-2
,xy=-1,3
∴原式=
=x2+xy+y2 x+y
=-(x+y)2-xy x+y
.13 3 6