At a Glance - Slope-Intercept Form
Another way to graph a line is to get it in slope-intercept form: y = mx + b, where
- m is the slope of the line
- b is the y-intercept
Since we are given a point of the line, and the slope, we can find an infinite number of other points on the line and connect them.
Remember: slope (m) is equal to the (change in y) / (change in x). Slope = "rise over run"
Slope-intercept form of a line: y = mx + b
Let's examine how to graph one of these equations: y = 2x + 1.
This is in slope-intercept form, so we know that the number in front of x is the slope (2), and that 1 is the y-intercept.
Start by plotting the y-intercept.
Next, since we know that the slope is , also known as , we know that another point will be two spaces up and one over (in the positive direction of course).
Finally, connect these points.
Look Out: when using slope-intercept form to graph lines, you must solve the equation for y, not x.
Graph the equation y = -½x – 2.
Graph the equation 4x + y = 7.
Graph the equation 2y = x.
Find the equation of the line in slope-intercept form.