21.5.2 Above or Below the x-Axis Tells You the Inequality
21.5 Linear Functions Tie Together Equations and Inequalities
Point 2 of 5
21.5.2 Above or Below the x-Axis Tells You the Inequality
Core idea
Where the line sits above the x-axis y>0, and where it sits below y<0, so reading the interval solves kx+b>0 or <0.
Module goal. Use the lens of the straight line to unify linear equations and inequalities, turning algebraic solving into "reading heights off the graph."
eastmath.com · 21.5 Linear Functions Tie Together Equations and Inequalities · 21.5.2 Above or Below the x-Axis Tells You the Inequality