①|-1|-

4

+（π-3）⁰+2^-2

=1-2+1+

1

4

=

1

4

②

x

x+3

=

1

x-2

+1

方程可化为x²-2x=x²+2x-3

解得x=

3

4

，

经检验x=

3

4

是方程的根．

③

x2-2x

x2-1

÷(x-1-

2x-1

x+1

)

=

x(x-2)

(x-1)(x+1)

•

(x+1)

x(x-2)

=

1

x-1

当x=

1

2

时，原式=-2．