m^2=2n
n^2=54m
54m=n^2=(m^2/2)^2=m^4/4
m≠0时
54m=m^3/4
m^3=216
m=6
n=m^2/2=18
m=0时,n=0
所以该方程组有两组解
m1=6,n1=18
m2=0,n2=0