📘 Class 8 · Mathematics

Chapter 2: Linear Equations in One Variable

6 lessons

Solving a linear equation in one variable means finding the single value of x that makes both sides of an equation equal — the unknown appears only to the first power, never squared or multiplied by itself. The core rule is simple: whatever is done to one side must be done to the other.

1
Introduction to Linear Equations
Introduction of linear equations in one variable and their solutions.
 2
Exercise 2.1 — Simple Equations
Solving simple equations having variable on one side.
 3
Exercise 2.2 — Applications
Applications of simple equations to real life problems.
 4
Exercise 2.3 — Variables on Both Sides
Solving equations that have variables on both sides.
 5
Exercise 2.4 — More Applications
Some more applications of linear equations.
 6
Exercise 2.5 — Reducing Equations
Reducing equations to simpler form — equations reducible to linear form.

A genuinely new skill

This is the first chapter where students solve for an unknown rather than simplify an existing expression. It also introduces translating a sentence into an equation — a skill every later algebra chapter, right through to Class 10's Quadratic Equations, depends on. "Five more than twice a number is seventeen" becomes 2x+5=17, giving x=6 — the translation step is usually harder than the solving step that follows it.

Where it goes wrong

Forgetting to apply an operation to both sides is the most common mistake, closely followed by a sign error when moving a term across the equals sign. When the variable appears on both sides, students often lose track of which side they've chosen to collect it on.