The answer is the same as the question because the expression doesn't factor in the set of integer numbers.
The best advise is to find the roots for 'x^2+3x-24=0', x1 and x2:

Click here to see the step by step solution for 'x^2+3x-24=0'

Then, you can factor using the formula:

x^2+3x-24 = (x - x1)(x - x2)

That is: