Writing Equations for Horizontal and Vertical Lines

Miacademy & MiaPrep Learning Channel

This video provides a clear and conceptual guide to understanding, writing, and graphing equations for horizontal and vertical lines. Moving beyond rote memorization, the lesson derives the equations by examining the slope and coordinate patterns of points on the lines. The narrator contrasts horizontal lines (zero slope, y equals a constant) with vertical lines (undefined slope, x equals a constant) to solidify student understanding of why the equations look different from standard linear forms. The video addresses the common confusion between "zero slope" and "undefined slope" by attempting to apply the slope-intercept form ($y=mx+b$) to both scenarios. It demonstrates that while horizontal lines simply have a slope of zero, vertical lines break the function model entirely, requiring a different approach based on shared x-coordinates. A final example problem synthesizes these concepts by asking students to identify equations for two intersecting lines on a graph without grid marks. This resource is highly valuable for Algebra 1 classrooms as it encourages conceptual deep diving rather than shortcut tricks. It is useful for introducing special linear cases, remediating misconceptions about slope, or reviewing before a unit on parallel and perpendicular lines. The step-by-step visual breakdowns make it accessible for visual learners and provide excellent pause points for checking student work.