1960 AMC 12 Question 18
AMC12 · 1960 AMC 12
The pair of equations $3^{x+y}=81$ and $81^{x-y}=3$ has:
no common solution
the solution $x=2,$ $y=2$
the solution $x=2\dfrac12,$ $y=1\dfrac12$
a common solution in positive and negative integers
none of these