how do i determine if a line pass through the origin

Question

equation y=2x -1

Answer 1

You can also test to see if

 

x = 0

y = 0

 

is a solution.  If yes, then the line passes through the origin.  If no, then it does not pass through the origin.

Answer 2

The slope intercept form is y = mx + b, where b is the y-intercept. In the equation y = 2x - 1, the y-intercept is -1. So, if you have an equation like y = 4x, there is no "b" term. Therefore, the y-intercept is zero, and the line passes through the origin.