The x-intercept(s) of a function are the points at which the graph of the function intersect the x-axis. They are also referred to as zeros since the intersections are the points where the y-value of the function is equal to zero. The zeros of a polynomial are also referred to as roots.
How to find the x-intercepts of a function
The x-intercepts of a function are the points at which the function is equal to 0, or, using typical function notation, f(x) = 0 (also y = 0). Thus, given the equation of a function, setting the function equal to 0 and solving for x will yield the x-intercept(s) of the function.
Find the x-intercept of the following function: f(x) = x2 - 9
x2 - 9 = 0
x2 = 9
x = = ±3
Therefore, the function has x-intercepts at x = -3 and x = 3: