Definition
X-intercept
An x-intercept marks a graph’s contact with the horizontal axis; its y-value is 0.
What it means
Look for where the graph touches or crosses the horizontal axis. Because every point on that axis has y = 0, setting y to 0 can help locate an x-intercept from an equation.
Remember it
On the x-axis, y is 0.
Example
For y = 2x − 6, set y = 0: 0 = 2x − 6, so 2x = 6 and x = 3. The x-intercept is the point (3, 0), or the value 3 when only the x-value is requested.
Watch for
A graph can have no x-intercept, one x-intercept, or several x-intercepts.
Common mix-up
At an x-intercept, y equals 0. Setting x to 0 finds a y-intercept instead.
Exact meaning
An x-intercept is a point where a graph meets the x-axis. Every x-intercept has y-coordinate 0. In some contexts, “the x-intercept” means the x-value of that point rather than the full ordered pair.