← Chapter 55 Chapter 56: Rearranging Formulae Chapter 57 →

Chapter 56: Rearranging Formulae

✏️ Explanation

Rearranging formulae means changing the subject (making a different variable the focus). Use inverse operations to isolate the required variable.

🔍 Why It Matters

Essential in science, engineering, and mathematics for solving practical problems with different known values.

✏️ Worked Example

Make t the subject of: v = u + at
Step 1: Subtract u from both sides
v - u = u + at - u
v - u = at
Step 2: Divide both sides by a
(v - u)/a = at/a
t = (v - u)/a

🔢 Practice Exercises

1. Make x the subject of: y = 3x + 5
2. Make r the subject of: A = πr²
3. Make h the subject of: V = lwh
4. Make b the subject of: a = 2b - 7
5. Make n the subject of: P = 4n + 3

⚠️ Common Mistakes

  • Not applying operations to both sides
  • Wrong order of operations
  • Sign errors when rearranging

✨ Quick Summary

Use inverse operations to isolate the required variable. Work systematically.