Math........

5/(2m)=1/(2m+3m)
5/(2m)=1/(5m)
2m=25m (Cross-multiply)
25m-2m=0
23m=0
m=0
But it will make the denominator of fractions 5/(2m) and 1/(2m+3m) equal to zero, therefore this equation has no solution.

2007-01-21 18:41:20 補充：
I think many people will forget to determine if the solution is acceptable.

5/2m=1/2m+3m
5/2m=1/5m
5*1/1=5m*2m/1
5=10m2
m2=5*1/10
m=1/2*2/1
m=1

5/(2m)=1/(2m+3m)
5 = [1/(2m+3m)] × (2m)
5=2m / 5m
25m = 2m
m = 0