问题 解答题
(1)计算:sin30°+2-1-(
5
-1)0+|-2|.
(2)化简并求值:(1+
1
x-1
x2
x2-1
,其中x=
2

(3)解方程(
x
x+1
)2-
x
x+1
-2=0
答案

(1)原式=

1
2
+
1
2
-1+2=2;

(2)原式=

x-1+1
x-1
÷
x2
(x+1)(x-1)

=

x
x-1
(x+1)(x-1)
x2

=

x+1
x

当x=

2
时,原式=
2
+1
2
=
2+
2
2

(3)设y=

x
x+1
,则原方程可化为y2-y-2=0,

变形得:(y-2)(y+1)=0,

解得:y=2或y=-1,

x
x+1
=2或
x
x+1
=-1,

解得:x=-2或x=-

1
2

经检验,x=-2与x=-

1
2
都是原分式方程的解.

单项选择题 A1/A2型题
判断题