Question

Where are the points for Y=-x^2+160x-5000

Answer 1

None are given.  You have to invent your own points that satisfy the given equation.

Examples:  If x = 0, y = -5000   =>  (0,-5000)
                   If x = 2, y = -(2)^2 + 160(2) - 5000 = 4 + 320 - 5000 => (2, -4676)

and so on.  Find as many such points as you want, using the same approach.