You group them since they have the same base (3). (3^4+1)*3^4m since they have almost the similar characters (ex. 3^4(m+1) is 3^4m+4). In the brackets we get (81+1) since 3^4 is 81, then we do the sum in the brackets (81+1) is 82 multiplied by 3^4m. Then we divide both sides with /82. 82/82 is one, 256/82 is 3. Since 3^4m and 3^1 have the same bases we just use 4m=1 where we get that m is 1/4.
