Question

The graph of a quadratic f(x) intersects the x-axis at –15 and 9. What is a possible

equation for f(x)?

Answer 1

the point that the function intercepts the x axis are the zeros of the function, where the products set equal to zero give you the x coordinate in which it intercepts.

x=-15 and x=9

set both equal to 0

x+15 and x-9

These are your two products

(x+15)(x-9)

or

x^2+6x-135