When a variable in an equation appears both in an exponent
of a constant and also not as an exponent of that constant,
as the variable x does in this one, then there is no algebraic
way to solve the equation. It can only be solved approximately
with technology involving iterative methods, actually trial and
error, i.e., by choosing values making the error less and less.
Technology (TI calculator) gives the following two approximations
for solutions:
x = -7.99909
and
x = 1.22154
Edwin