问题 解答题
计算:(1)
x2+9x
x2+3x
+
x2-9
x2+6x+9

(2)
2-x
x-1
÷(x+1-
3
x-1
)
答案

(1)原式=

x(x+9)
x(x+3)
+
(x+3)(x-3)
(x+3)2
=
x+9
x+3
+
x-3
x+3
=
2(x+3)
x+3
=2;

(2)原式=-

x-2
x-1
÷
x2-4
x-1
=-
x-2
x-1
x-1
(x+2)(x-2)
=-
1
x+2

单项选择题
单项选择题