16^m=4*2^(2n-2)
2^4m=2^2*2^(2n-2)
2^4m=2^2n
27^n=9*3^(m+3)
3^3n=3^2*3^(m+3)
3^3n=3^(m+5)
3n=m+5①
2n=4m②
②÷2
n=2m③
③代入①
6m=m+5
m=1
n=2