Mathematics · Class 7
Simple Equations
Forming and solving linear equations in one variable from word problems.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Simple equations in one variable are solved by maintaining balance — transposing terms, applying inverse operations. Foundation for algebra in Classes 8–10.
Forming Equations
- Translate word statements to algebra
- 'Number increased by 7 gives 15' → x + 7 = 15
- Consecutive integers: n, n+1, n+2
Solving Methods
- Add/subtract same number on both sides
- Multiply/divide both sides by same non-zero number
- Transpose: change side, change sign
Applications
Age problems, perimeter problems, and number puzzles in NCERT use single-variable linear equations.
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Example 1: Solve
Solve 3x − 7 = 11.
- 13x = 11 + 7 = 18
- 2x = 18 ÷ 3
Answer
x = 6
Example 2: Word Problem
Sum of a number and 12 is 30. Find the number.
- 1Let number = x
- 2x + 12 = 30
- 3x = 18
Answer
18
Key Points to Remember
- ✓ Check solution in original equation
- ✓ LHS and RHS must stay equal
- ✓ Bracket expansion may be needed first
Exam Tips
- • Define variable at start of word problems
- • Show transposition steps
Practice MCQs — Simple Equations
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Solution of x + 9 = 4 is: