Answer:
x ∈ {−0.766664695962, 2, 4}
Explanation:
The equation is a combination of polynomial and exponential functions. There are no algebraic methods for solving such an equation. Graphical and iterative methods work nicely, though.
The attached graph shows integer solutions at x=2 and x=4. There is also an irrational negative solution near x = −0.766664695962. The latter was found by using Newton's method iteration on the graphical value of -0.767.