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Squares And Square Roots 8 Class 8 Exam Prep Revision — Grandmaster Guide

A

Ayush (Founder)

Exam Strategist

Last Updated: 2026-04-20
  • a² - b² = (a + b)(a - b)
  • (a + b)² = a² + 2ab + b²
  • (a - b)² = a² - 2ab + b²
  • (a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
  • √(a²) = a
  • (√a)² = a
  • √(ab) = √a × √b
  • √(a/b) = √a / √b
  • (√a)ⁿ = aⁿ⁄²
  • a² = (a) × (a)
  • √a × √a = a

🪤 The 5 Mistakes That Cost Marks

  • Not simplifying the expression before finding the square root
  • Not using the formula (a + b)² = a² + 2ab + b² to simplify expressions
  • Not using the formula a² - b² = (a + b)(a - b) to factorize expressions
  • Not using the formula (√a)² = a to simplify square root expressions
  • Not using the formula √(ab) = √a × √b to simplify square root expressions

✏️ 3 Solved PYQs

  • Question 1: Simplify (√5)² Step 1: Use the formula (√a)² = a Step 2: Substitute a = 5 into the formula Step 3: Simplify the expression to get the answer Answer: 5
  • Question 2: Find the value of an if (a + 3)² = 64 Step 1: Use the formula (a + b)² = a² + 2ab + b² Step 2: Substitute b = 3 and the given value into the formula Step 3: Simplify the expression to get a² + 6a + 9 = 64 Step 4: Rearrange the equation to get a² + 6a - 55 = 0 Step 5: Factorize the equation to get (a + 11)(a - 5) = 0 Step 6: Solve for a to get a = -11 or a = 5
  • Question 3: Simplify √(16/9) Step 1: Use the formula √(a/b) = √a / √b Step 2: Substitute a = 16 and b = 9 into the formula Step 3: Simplify the expression to get √16 / √9 Step 4: Simplify the square roots to get 4/3

🧠 The One Thing Most Students Get Wrong

  • Most students get wrong the simplification of expressions involving square roots and the use of formulas to simplify expressions
  • They often forget to use the formulas (a + b)² = a² + 2ab + b² and a² - b² = (a + b)(a - b) to simplify expressions
  • They also often forget to use the formulas (√a)² = a and √(ab) = √a × √b to simplify square root expressions

👁️ Ayush's Note

  • To excel ∈ squares and square roots, practice simplifying expressions using the formulas
  • Make sure to use the formulas (a + b)² = a² + 2ab + b² and a² - b² = (a + b)(a - b) to simplify expressions
  • Also, use the formulas (√a)² = a and √(ab) = √a × √b to simplify square root expressions
  • Practice solving questions involving squares and square roots to build confidence and speed

🔁 Last 5 Minutes Box

  • Go through the formulas one last time
  • Make sure to remember the formulas (a + b)² = a² + 2ab + b² and a² - b² = (a + b)(a - b)
  • Also, remember the formulas (√a)² = a and √(ab) = √a × √b
  • Take a few deep breaths and stay calm
  • Read each question carefully and choose the correct answer

📝 Practice MCQs

1. What is the value of (√9)²?

A) 3

B) 9

C) 12

D) 15

Answer: B) 9, using the formula (√a)² = a

2. What is the value of (2 + 3)²?

A) 20

B) 25

C) 30

D) 35

Answer: B) 25, using the formula (a + b)² = a² + 2ab + b²

3. What is the value of √(16/4)?

A) 1

B) 2

C) 3

D) 4

Answer: B) 2, using the formula √(a/b) = √a / √b

4. What is the value of (5 - 2)²?

A) 9

B) 12

C) 15

D) 18

Answer: A) 9, using the formula (a - b)² = a² - 2ab + b²

5. What is the value of (√4) × (√9)?

A) 5

B) 6

C) 12

D) 15

Answer: B) 6, using the formula √(ab) = √a × √b


🚀 Ready to Ace Your Exam?

Put your knowledge to the test! Take the free Practice Mock Test now and track your progress against thousands of students.

📚 Academic References

Content verified against peer-reviewed research:

  1. �Let the People Rap�: Cultural Rhetorics Pedagogy and Practices U... — Journal of Basic Writing (2019) 🔓 — DOI ↗
  2. Frustration and Hope: Examining Students� Emotional Responses to ... — Journal of Basic Writing (2019) — DOI ↗
  3. Editors' Column — Journal of Basic Writing (2019) — DOI ↗

🔓 = Open Access article

🎬 Watch video explanations on YouTube →


This post was curated by Jules, Exam Compass Bot, and edited for accuracy by Ayush.


📚 Related Topics

Continue your revision with these related guides:

  • 📖 Data Handling 8 Class 8 Exam Prep Revision — Grandmaster Guide
  • 📖 Rational Numbers 8 Class 8 Exam Prep Revision — Grandmaster Guide
  • 📖 Application Of Integrals Class 12 Exam Prep Revision — Grandmaster Guide
  • 📖 Areas Related To Circles Class 10 Exam Prep Revision — Grandmaster Guide
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Prepared for Scholar
Date: 2026-04-20
CATEGORY: Exam Notes
  • a² - b² = (a + b)(a - b)
  • (a + b)² = a² + 2ab + b²
  • (a - b)² = a² - 2ab + b²
  • (a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
  • √(a²) = a
  • (√a)² = a
  • √(ab) = √a × √b
  • √(a/b) = √a / √b
  • (√a)ⁿ = aⁿ⁄²
  • a² = (a) × (a)
  • √a × √a = a

🪤 The 5 Mistakes That Cost Marks

  • Not simplifying the expression before finding the square root
  • Not using the formula (a + b)² = a² + 2ab + b² to simplify expressions
  • Not using the formula a² - b² = (a + b)(a - b) to factorize expressions
  • Not using the formula (√a)² = a to simplify square root expressions
  • Not using the formula √(ab) = √a × √b to simplify square root expressions

✏️ 3 Solved PYQs

  • Question 1: Simplify (√5)² Step 1: Use the formula (√a)² = a Step 2: Substitute a = 5 into the formula Step 3: Simplify the expression to get the answer Answer: 5
  • Question 2: Find the value of an if (a + 3)² = 64 Step 1: Use the formula (a + b)² = a² + 2ab + b² Step 2: Substitute b = 3 and the given value into the formula Step 3: Simplify the expression to get a² + 6a + 9 = 64 Step 4: Rearrange the equation to get a² + 6a - 55 = 0 Step 5: Factorize the equation to get (a + 11)(a - 5) = 0 Step 6: Solve for a to get a = -11 or a = 5
  • Question 3: Simplify √(16/9) Step 1: Use the formula √(a/b) = √a / √b Step 2: Substitute a = 16 and b = 9 into the formula Step 3: Simplify the expression to get √16 / √9 Step 4: Simplify the square roots to get 4/3

🧠 The One Thing Most Students Get Wrong

  • Most students get wrong the simplification of expressions involving square roots and the use of formulas to simplify expressions
  • They often forget to use the formulas (a + b)² = a² + 2ab + b² and a² - b² = (a + b)(a - b) to simplify expressions
  • They also often forget to use the formulas (√a)² = a and √(ab) = √a × √b to simplify square root expressions

👁️ Ayush's Note

  • To excel ∈ squares and square roots, practice simplifying expressions using the formulas
  • Make sure to use the formulas (a + b)² = a² + 2ab + b² and a² - b² = (a + b)(a - b) to simplify expressions
  • Also, use the formulas (√a)² = a and √(ab) = √a × √b to simplify square root expressions
  • Practice solving questions involving squares and square roots to build confidence and speed

🔁 Last 5 Minutes Box

  • Go through the formulas one last time
  • Make sure to remember the formulas (a + b)² = a² + 2ab + b² and a² - b² = (a + b)(a - b)
  • Also, remember the formulas (√a)² = a and √(ab) = √a × √b
  • Take a few deep breaths and stay calm
  • Read each question carefully and choose the correct answer

📝 Practice MCQs

1. What is the value of (√9)²?

A) 3

B) 9

C) 12

D) 15

Answer: B) 9, using the formula (√a)² = a

2. What is the value of (2 + 3)²?

A) 20

B) 25

C) 30

D) 35

Answer: B) 25, using the formula (a + b)² = a² + 2ab + b²

3. What is the value of √(16/4)?

A) 1

B) 2

C) 3

D) 4

Answer: B) 2, using the formula √(a/b) = √a / √b

4. What is the value of (5 - 2)²?

A) 9

B) 12

C) 15

D) 18

Answer: A) 9, using the formula (a - b)² = a² - 2ab + b²

5. What is the value of (√4) × (√9)?

A) 5

B) 6

C) 12

D) 15

Answer: B) 6, using the formula √(ab) = √a × √b


🚀 Ready to Ace Your Exam?

Put your knowledge to the test! Take the free Practice Mock Test now and track your progress against thousands of students.

📚 Academic References

Content verified against peer-reviewed research:

  1. �Let the People Rap�: Cultural Rhetorics Pedagogy and Practices U... — Journal of Basic Writing (2019) 🔓 — DOI ↗
  2. Frustration and Hope: Examining Students� Emotional Responses to ... — Journal of Basic Writing (2019) — DOI ↗
  3. Editors' Column — Journal of Basic Writing (2019) — DOI ↗

🔓 = Open Access article

🎬 Watch video explanations on YouTube →


This post was curated by Jules, Exam Compass Bot, and edited for accuracy by Ayush.


📚 Related Topics

Continue your revision with these related guides:

  • 📖 Data Handling 8 Class 8 Exam Prep Revision — Grandmaster Guide
  • 📖 Rational Numbers 8 Class 8 Exam Prep Revision — Grandmaster Guide
  • 📖 Application Of Integrals Class 12 Exam Prep Revision — Grandmaster Guide
  • 📖 Areas Related To Circles Class 10 Exam Prep Revision — Grandmaster Guide