问题 解答题
(1)化简:(
b
ab
+b
+
a
ab
-a
)÷
ab
a
+
b
a-b
a
+
b

(2)解方程组
x2-3xy+2y2+4x+3y-1=0
2x2-6xy+y2+8x+2y-3=0
答案

(1)原式=(

b
b
b
(
a
+
b
)
+
a
• 
a
a
(
b
-
a
)
)•
a
+
b
ab
a-b
a
+
b

=(

b
a
+
b
+
a
b
-
a
)•
a-b
ab

=

b-
ab
+a+
ab
b-a
a-b
ab

=

-a-b
ab

(2)

x2-3xy+2y2+4x+3y-1=0  ①
2x2-6xy+y2+8x+2y-3=0  ②

①×2得:2x2-6xy+4y2+8x+6y-2=0,③

③-②得;3y2+4y+1=0,

解得:y1=-1,y2=-

1
3

把y1=-1代入①得:x2+7x-2=0,

解得:x1=

7+
57
2
,x2=
7-
57
2

把y2=-

1
3
代入①得:x2+5x-
16
9
=0,

解得:x1=-

16
3
,x2=
1
3

∴方程组的解为

x1=
1
3
y1=-
1
3
x2=-
16
3
y2=-
1
3
x3=
-7+
57
2
y3=-1
x4=
-7-
57
2
y4=-1

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