To simplify the given equation, we can first distribute the terms on both sides:

3x(x-4) - (x+1)(x-8) = 2x^2 + 5

Expanding the left side:

3x^2 - 12x - (x^2 - 8x + x - 8) = 2x^2 + 5

Simplifying:

3x^2 - 12x - x^2 + 8x - x + 8 = 2x^2 + 5

Combining like terms:

2x^2 - 5x + 8 = 2x^2 + 5

Since the x^2 terms are the same on both sides, we can combine the equation as:

-5x + 8 = 5

Now, we can solve for x:

-5x = -3
x = 3/5

Therefore, the solution to the equation is x = 3/5.