Slope-Intercept Form and Graphing

Algebra Foundation

Algebra 1

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Algebra 1 · Unit 5 · Topic 5.2

Slope-Intercept Form and Graphing

The equation y = mx + b describes a nonvertical line with slope m and y-intercept (0, b).

Definition and explanation

The equation y = mx + b describes a nonvertical line with slope m and y-intercept (0, b). In a model, m has output-units per input-unit while b has output-units.

Worked example

Graph y = (3/2)x − 4. Start at (0, −4), then move right 2 and up 3 to reach (2, −1). Both points satisfy the equation and determine the line.

Common mistake

The slope 3/2 is a ratio, not the y-intercept or a second coordinate.

Key takeaway

The equation y = mx + b describes a nonvertical line with slope m and y-intercept (0, b).

Explain each step of the worked example, then check the units, signs, and conditions that apply.

Further reading

Topic coverage was checked against the openly available OpenStax Elementary Algebra 2e and Algebra and Trigonometry 2e textbooks. The explanations and examples on this site are independently written; textbook prose, exercises, and artwork are not reproduced.