3的2m次方+3n次方-1=3的2m次方*3的3n次方/3=(3的m次方)^2*(3的n次方)^3/3=5^2*2^3/3=200/33的2n次方+3m次方-1=3的2n次方*3的3m次方/3=(3的n次方)^2*(3的m次方)^3/3=2^2*5^3/3=500/3
3^2n+3^m-1 =(3^n)^2+3^m/3 =2^2+5/3 =4+5/3 =17/3
