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Overview
Foundations of Mathematics and Pre-Calculus 10 (MAT421A)
Relations and Functions
12. Describe and represent linear relations using words, ordered pairs, tables, graphs, equations
12.5 Special case of linear equations: Horizontal lines
Horizontal Lines
An equation of the form y = c graphs as a horizontal line, where every point shares the same y-value.
What You'll Learn
An equation y = c (c a constant) graphs as a horizontal line.
Every point on a horizontal line shares the same y-value.
A horizontal line has a slope of 0.
y does not change as x changes on a horizontal line.
A vertical line is the opposite special case, with undefined slope.
What You'll Practice
1
Writing equations from pairs of points with matching y-values
2
Identifying horizontal line equations passing through given points
3
Recognizing when coordinate pairs form horizontal lines
Why This Matters
Understanding horizontal lines is essential for graphing functions and analyzing real-world situations where values remain constant, like temperature plateaus or fixed costs. This concept builds your foundation for more complex linear equations and helps you quickly identify special cases in algebra and coordinate geometry.
Before You Start — Make Sure You Can:
This Unit Includes
3 Video lessons
Practice exercises
Learning resources
Skills
Horizontal Lines
Linear Equations
Slope
Coordinate Geometry
y-intercept
PEI Curriculum Aligned