What are the zeros of f(x) = x2 + x - 20?

So when you use an equation like this, you use the PS2 method. P means you find the product of the first and last numbers in the equation, so in your problem it would be -20. S means the number in front of the 2nd number, and in your problem it would be 1 because anything times 1 is itself. The 2 means that you need to find two numbers that multiply to your product: -20, and the sum which is 1. And the two numbers are -4 and 5. And since it’s equal to zero, it’s x=-5 and x=4. Your welcome

there are infinitely many solutions.