To solve the equation 2x + 3x = 45, we can combine like terms on the left side of the equation:

2x + 3x = 5x

So the equation becomes 5x = 45.

To isolate x, we can divide both sides of the equation by 5:

5x/5 = 45/5

x = 9

Therefore, the solution to the equation is x = 9.