1.2/m²-4-1/2m-4
=2/(m+2)(m-2)-1/2(m-2)
=4/2(m+2)(m-2)-(m+2)/2(m+2)(m-2)
=(4-m-2)/2(m+2)(m-2)
=-1/2(m+2)
解方程：
1.x/x-1-2/x=1
两边乘以x(x-1)得
x²-2(x-1)=x(x-1)
x²-2x+2=x²-x
-x=-2
∴x=2
检验：x=2是方程的解
2.1/x-2=3-x/2-x-3
两边乘以(x-2)得
1=x-3-3(x-2)
2x=4
x=2
检验：x=2是增根
∴方程无解