5/2 ^2 = 6 1/4 = 6.25
3/4^3 = 27/64 = 0.4201875
6 1/4 + 27/64 = 6 43/64 (mixed number)
6.25 +0.421875 = 6.671875 (decimal)
not sure what format you need, since the question was in fraction form, I think you need to answer using a mixed number though.
