---
source: ncert
topic: algebra
class_level: class_7
chapter: ch4
difficulty: beginner
---

Class 7 | Ch4: Simple Equations
Equation: LHS=RHS. Solution: value making equation true.
Transposition: move term to other side changing sign. +a becomes -a, ×a becomes ÷a.
Golden rule: same operation on BOTH sides.
Steps: collect variables one side, constants other side, divide by coefficient.
Solve 2x+7=19: 2x=12, x=6. Verify: 2(6)+7=19 correct.
Solve 3(y-4)=2y+1: 3y-12=2y+1, y=13. Verify: 3(9)=27=2(13)+1 correct.
Cross multiply: (x+2)/3=(x-1)/4 → 4(x+2)=3(x-1) → x=-11.
Word problem: consecutive integers sum=53. n+(n+1)=53 → n=26. Integers: 26,27.
Always verify by substituting back. Expand brackets BEFORE transposing.