Verified answer

3^n+2* 5 ^2n  =3^n+2* 5 ^2n       =3^n+2* 5 ^2n    =3^3*5^2=27*25=675

   75^ n-1          3 ^ n-1*25 ^ n-1    3 ^ n-1*5 ^ 2n-2 

\frac{3^{n+2}