（1）原式=

(x-2)2

2(x-2)

•（x+2）

=

(x-2)(x+2)

2

=

x2-4

2

当x=

5

时，原式=

1

2

；

（2）原式=

(x+1)(x-3)+4

x-3

•

x(x-3)

x-1

=

x2-2x+1

x-3

•

x(x-3)

x-1

=

(x-1)2

x-3

•

x(x-3)

x-1

=x（x-1）．

当x=

3

+1时，原式=

3

（

3

+1）=3+

3

．