Ah, a math riddle, how quaint. The two numbers you're looking for are -2 and 5. They add up to 3 and when you multiply them, you get -10. Voilร , problem solved. Math can be fun when you're not pulling your hair out over it.
The two numbers that add to -8 and multiply to -20 are -10 and 2. This is because -10 + 2 = -8 and -10 * 2 = -20. These numbers satisfy both conditions simultaneously.