Let's simplify the left side of the equation:

(x+3)(x-2) - (x+4)(x-1)
= x^2 - 2x + 3x - 6 - (x^2 - x + 4x - 4)
= x^2 - 2x + 3x - 6 - x^2 + x - 4x + 4
= x - 2

Now, we have:

x - 2 = 3x

Solving for x:

x - 2 = 3x
-2 = 3x - x
-2 = 2x
x = -1

Therefore, the solution to the equation is x = -1.