[tex] 2^{3n+1} *3 ^{n+1} +8 ^{n} *3 ^{n+3} +4 ^{n} *6 ^{n+1} =[/tex]
[tex] 2*2^{3n} *3 ^{n+1} +(2 ^{3}) ^{n} *3 ^{n+3} + (2^{2}) ^{n} *(2*3) ^{n+1} =[/tex]
[tex] 2*2^{3n} *3 ^{n+1} +2 ^{3} ^{n} *3 ^{n+3} + 2^{3} ^{n} *2*3 ^{n+1} =[/tex]
[tex]2^{3n} *3 ^{n+1}*( 2 +3 ^{2} + 2) =2^{3n} *3 ^{n+1}*13[/tex]