第106页 - 通城学典课时作业本八年级数学人教版南通专版

A

D

$x-1$

$解：原式=\frac {2a}{(a+2)(a-2)}·\frac {a-2}a+\frac a {a+2}$

$=\frac 2 {a+2}+\frac a {a+2}$

$=1$

解:原式$=\frac {a+1-a}{a+1}×\frac {(a+1)(a-1)}{a(a-1)}$

$=\frac {1}{a+1}×\frac {a+1}{a}$

$=\frac {1}{a}$

解:原式$=\frac {a-3+1}{(a+3)(a-3)}×\frac {2(a+3)}{a-2}$

$=\frac {a-2}{(a+3)(a-3)}×\frac {2(a+3)}{a-2}$

$=\frac {2}{a-3}$

解:原式$=\frac {2(m-3)}{(m-3)(m+3)}×\frac {m+3}{2(m+1)}-\frac {m}{m+1}$

$=\frac {1}{m+1}-\frac {m}{m+1}$

$=\frac {1-m}{m+1}$

$=\frac {1-2}{2+1}$

$=-\frac {1}{3}$

B

D

1