How do you find the slope and intercept for #x=-4#?
graph the line.
look at it.
if it crosses both the x axis and the y axis, then it will have 2 intercepts (the x intercept and the y intercept).
The x intercept is where it crosses the x axis
the y intercept is where it crosses the y axis.
This line goes through many many points. Here are some of them: (-4, 0), (-4, 1), (-4, 3), (-4, 5), (-4, -3), (-4, -2),.....
notice anything about these points?
The x value is always -4.
When you plot these points, you will also notice that the line is parallel to one of the axes.
You will be able to easily spot the one intercept where it will cross only one of the axes. It won't cross the other axes because it is parallel to it.
The slope is calculated by determining the ratio between change in Y to the change in X for any pair of selected points.