The quadratic equation for this would be f(x) = 5x^2 - 10x - 120.
In order to find that, we need to start by taking our x intercept values and setting them equal to zero.
x = 6 ----> subtract 6 from both sides
x - 6 = 0
x = -4 ----> add 4 to both sides
x + 4 = 0
Now that we have both of these zero terms, we can multiply them to get a standard form.
f(x) = (x - 6)(x + 4)
And while this will give us the zeros we need, it will no give us the lead coefficient. So we must multiply by the desired lead coefficient.
f(x) = 5(x - 6)(x + 4)
f(x) = 5(x^2 - 6x + 4x - 24)
f(x) = 5(x^2 - 2x - 24)
f(x) = 5x^2 - 10x - 120
