Re: 81^3-27^3/3^7
[#permalink]
26 Jul 2021, 09:27
An alternative solution to this is to realize that 81 and 27 can both be converted to 3^x forms.
81 = 3^4
27 = 3^3
The equation becomes ((3^4)^3 + (3^3)^3) / 3^7 = (3^12 + 3^9) / 3^7. = 3^5 + 3^2.
3^5 + 3^2 = 3^2(3^3 +1) = 234.
**Although not as efficient as the method above ^. I find it important to be able to solve these problems in various ways so you can check your work thoroughly if you have time.
Good luck!