Assuming that the inequality you were going for was a ≤, set both polynomials less than or equal to 0.
x - 3 ≤ 0
x + 5 ≤ 0
For the first equation add 3 to both sides of the inequality. For the second, subtract 5 from both sides.
x ≤ 3
x ≤ - 5
These would be your solutions I guess, however, if you want to expand upon that, your actual answer is (- ∞, - 5] because if you were to plot these two inequalities on a number line, that is where the overlap would occur.