not sure of the background of this question so this is just my observation on this.
since the equation
which is a fixed number and positive
then m and n will have be both positive. if you plug any number other than 0 you cannot get the 33^3 only m=0 and n=0 will work
so if
so if
so your answer of #2 (0,33)(33,0) appears to be correct
the answer to this seems to be just looking at the equation and seeing what really is possible given the constraint was a big hint.
again this is just my observation. there may be something too that I don't see in this, (my disclaimer anyway)
hope this helps. (some)