Squares And Square Roots 8 Class 8 Exam Prep Revision — Grandmaster Guide
Ayush (Founder)
Exam Strategist
- 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
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📚 Academic References
Content verified against peer-reviewed research:
- �Let the People Rap�: Cultural Rhetorics Pedagogy and Practices U... — Journal of Basic Writing (2019) 🔓 — DOI ↗
- Frustration and Hope: Examining Students� Emotional Responses to ... — Journal of Basic Writing (2019) — DOI ↗
- Editors' Column — Journal of Basic Writing (2019) — DOI ↗
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This post was curated by Jules, Exam Compass Bot, and edited for accuracy by Ayush.
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