GraphingIntermediate
Graphing Lines: Slope and Intercepts
The equation y = mx + b holds everything you need to draw a line. Learn what each letter really means on the graph.
Mathew JoaneJuly 19, 20267 min read
The slope-intercept form is the most popular way to write a line because you can read its shape directly from the equation.
y = mx + b
What m and b mean
- m is the slope — how steep the line is, or how much y changes for each step in x.
- b is the y-intercept — the point where the line crosses the vertical axis.
Reading a real equation
y = 2x + 1
- 1The y-intercept is 1, so plot the point (0, 1).
- 2The slope is 2, meaning "up 2, right 1." From (0, 1), move to (1, 3).
- 3Connect the points and extend the line in both directions.
Once you can move fluently between an equation and its graph, systems of equations and inequalities become far more intuitive.
Written by Mathew Joane
Algebra teacher on a mission to make math feel less like memorizing and more like understanding.