Since you mention "exponential", I suspect the equation is supposed to read

Recall that
, so we can simplify the left side to get

and since 81 = 3⁴,

because the bases in the expressions on either side are the same.
Solve for x :
(2x + 3) + (x - 2) = 4
3x + 1 = 4
3x = 3
x = 1