a^m+1* b^n+2*a^2n-1*b^2m=a^5*b^3
a^(m+1+2n-1)* b^(n+2+2m)=a^5*b^3
a^(m+2n)* b^(n+2+2m)=a^5*b^3
a和b的次数分别相等
所以m+2n=5
n+2+2m=3
相加
m+2n+n+2+2m=5+3
3m+3n=6
m+n=2