Question

化簡分式計算：

x-3

x2-1

÷

x2+x

x2+2x+1

-

1

x-1

，并選擇一個你認為合適的x的值，求代數式的值．

Answer 1

原式=

x-3

(x+1)(x-1)

•

(x+1)2

x(x-3)

-

1

(x-1)

 
=

x+1

x(x-1)

-

1

(x-1)

            
=

1

x(x-1)

．
當x=2時，原式=

1

2(2-1)

=

1

2

．