Find an equation of the vertical line that passes through (4,5).

Question

im not sure how to do this with just one point... can someone walk me through please?

 

Answer 1

Rachel,

 

 Imagine a vertical line on the xy-plane (a two dimensional graph with x and y axes). YOu can see by looking at the vertical line that, if you pick a point that's on the line, the y-coordinate changes, but the x-coordinate is always the SAME. SO, no matter what value y is, x always stays the same. Therefore, since you have the point (4,5), your x-coordinate will always be 4 if you're working with a vertical line. Thus, your equation for a vertical line is:

 

x=4.