X and Y Intercepts

[Opening view contains the title over a graph.]

Narrator: In this video we’re going to discuss how to find the X and the Y intercepts of a line.

[Title disappears and the graph behind it is shown with a diagonal line passing through the Y axis at 0,3 and then through the X axis at a place between 1 and 2.]

First of all the X intercept is anywhere the line crosses the X axis. Here’s the X axis. [X axis is highlighted as the rest of the graph is dimmed from view for a moment.] This particular crosses the at this point. [Refers to the location the line crosses the X axis.]

The Y intercept is anywhere the line crosses the Y axis. In this case it’s right about here. [Indicates to where the line crosses the Y axis.] At the point, X is 0, is where the line will cross the Y axis because the point where X is 0 is on the Y axis. Similarly the point at which the line crosses the X axis is when the Y value is 0. So we look along the Y axis and we come to 0. 0 is the only value on the Y axis that is also on the X axis. So Y equal to 0 is on the X axis. So the point where the line crosses the X axis, the Y value, the Y value will always be 0. The X value will change depending on the line, but anytime the line crosses the X axis the Y value is 0.

Anytime the line crosses the Y axis, the X value has to be 0. [Writes (0, ) on the screen.] Now the Y value may be different, the Y value will be where it crosses. Anytime the Y crosses anytime the line crosses the Y axis, the X coordinate has to be 0. So the part that’s left is to estimate the X value for the X intercept and the Y value for the Y intercept.

If we look at the X intercept, it’s somewhere between 1 and 2 on the X axis. Let’s estimate it at about 1.5. [1.5 appears in the information for the X intercept (1.5, 0).] Now for the Y value at the Y intercept. If we look here closely, it looks as though the line passes right through the spot on the Y axis equal to 3. [3 appears in the information for the Y intercept, (0,3).] So in this case, we will guess 3. And we estimate our Y intercept to be at 0 comma 3.

[End of video.]