(x)(x)(x)=(x)^x

(-1)(-1)(-1)=(-1)^-1, both sides equal -1
(1)(1)(1)=(1)^1, both sides equal 1
(3)(3)(3)=(3)^3, both sides = 27

Note that 0 is NOT a solution since 0^0 is not defined.
Note also that -3 is not a solution, since (-3)(-3)(-3) is -27,
but (-3)^(-3) is -1/27.

So the solution set is {-1, 1, 3}

Edwin