Solve one-variable equations, work with inequalities, and recognize how independent and dependent variables relate.
Quick read-throughs in plain language — then hit the videos below.
x + 7 = 15 → subtract 7 from both sides → x = 8. Same rule for × and ÷.
Always check: plug your answer back in. 8 + 7 = 15 ✓
Try it
Solve n − 9 = 14.
By the end of this unit, you should be able to:
Each video covers one topic from this unit — read the short blurb below to find the right one.
Add, subtract, multiply, or divide both sides to isolate x.
Watch on YouTubeHarder one-step equations with fractions and negatives.
Watch on YouTubeSymbols like < and ≥ and what they mean on a number line.
Watch on YouTubeSolve inequality problems the same way you solve equations.
Watch on YouTubeShade the number line to show all solutions.
Watch on YouTubeExtra examples graphing inequality solutions.
Watch on YouTubeWhich quantity you choose and which one depends on it.
Watch on YouTubeIdentify input and output in tables and graphs.
Watch on YouTubeTurn a story problem into an equation you can solve.
Watch on YouTubeA longer walk-through of tricky word-problem setups.
Watch on YouTubeAdam's curated problem sets — preview here or open in Google Drive.
Hand-picked links from Khan Academy and trusted worksheet libraries.
A few quick questions to make sure the big ideas stuck. Retake as many times as you want.
Unit 4: Equations & Inequalities
Solve for x: x + 7 = 12
