计算:1/x2−4x+4-x/x2−4+1/2x+4.

问题描述:

计算:

1
x2−4x+4
-
x
x2−4
+
1
2x+4

原式=

1
(x−2)2
-
x
(x+2)(x−2)
+
1
2(x+2)
=
2(x+2)−2x(x−2)+(x−2)2
2(x−2)2(x+2)
=-
(x+2)(x−4)
2(x−2)2(x+2)
=-
x−4
2(x−2)2