There are infinitely many possible pairs of numbers that can be multiplied and added to get -1/2. Here are some examples:
1 and -1/2 can be multiplied to get -1/2
2 and -2 can be multiplied to get -4, and then dividing by 8 gives -1/2
-3 and 1 can be multiplied to get -3, and then dividing by 6 gives -1/2
And so on. In general, if you have two numbers x and y, then their product is xy and their sum is x + y. If you want these to equal -1/2, you can solve the equation xy + x + y = -1/2 for one variable in terms of the other, and then substitute that expression into the other equation. This will give you a quadratic equation that you can solve for one of the variables, and then use that value to find the other variable.