Math Homework. Do It Faster, Learn It Better.
Finding the Equation of a Line from Its Graph
Suppose you are given the graph of a line in the coordinate plane, and asked to find its equation.
If you can find the -intercept and the slope , you can write the equation in slope-intercept form (unless, of course, it's a vertical line .)
Example :
Find the equation of the line shown.
Here the line crosses the -axis at , so the -intercept is .
To find the slope, use the two points and and substitute these in the slope formula: