We Distribute Yet Things Multiply — Class 8 Mathematics NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 8 Mathematics chapter "We Distribute Yet Things Multiply" — 8 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 8 Mathematics chapter "We Distribute Yet Things Multiply" — 8 important questions with detailed answers fo…
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Key Questions Covered:
- Expand: 3(2x + 5)
- Simplify: (x + 2)(x + 3)
- Evaluate the identity: (a + b)² = a² + 2ab + b² for a = 2, b = 3
- Multiply: (2x + 3)(x - 2)
- Use the identity (a - b)² = a² - 2ab + b² to find (5 - 3)²
- Expand: -2(3x - 4y)
- + 2 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| Expand: 3(2x + 5) | ✓ Solved |
| Simplify: (x + 2)(x + 3) | ✓ Solved |
| Evaluate the identity: (a + b)² = a² + 2ab + b² for a = 2… | ✓ Solved |
| Multiply: (2x + 3)(x - 2) | ✓ Solved |
| Use the identity (a - b)² = a² - 2ab + b² to find (5 - 3)² | ✓ Solved |
| Expand: -2(3x - 4y) | ✓ Solved |
Showing 6 of 8 questions
Q1: Expand: 3(2x + 5)
We use the distributive property to expand this expression.
Step 1: Recall the distributive property
a(b + c) = ab + ac
Step 2: Identify a, b, and c
a = 3
b = 2x
c = 5
Step 3: Apply the distributive property
3(2x + 5) = 3(2x) + 3(5)
Step 4: Multiply
3(2x) = 6x
3(5) = 15
Step 5: Combine
3(2x + 5) = 6x + 15
Answer: 3(2x + 5) = 6x + 15
Q2: Simplify: (x + 2)(x + 3)
We need to multiply two binomials using the distributive property (FOIL method).
Step 1: Use the distributive property twice
(x + 2)(x + 3) = x(x + 3) + 2(x + 3)
Step 2: Distribute x
x(x + 3) = x² + 3x
Step 3: Distribute 2
2(x + 3) = 2x + 6
Step 4: Combine like terms
(x + 2)(x + 3) = x² + 3x + 2x + 6 = x² + 5x + 6
Step 5: Alternative - FOIL method
First: x × x = x²
Outer: x × 3 = 3x
Inner: 2 × x = 2x
Last: 2 × 3 = 6
Result: x² + 3x + 2x + 6 = x² + 5x + 6
Answer: (x + 2)(x + 3) = x² + 5x + ...
Q3: Evaluate the identity: (a + b)² = a² + 2ab + b² for a = 2, b = 3
We verify the algebraic identity by substituting values.
Step 1: Write the identity
(a + b)² = a² + 2ab + b²
Step 2: Substitute a = 2 and b = 3
Left side: (2 + 3)² = (5)² = 25
Step 3: Evaluate the right side
a² + 2ab + b² = 2² + 2(2)(3) + 3²
= 4 + 2(6) + 9
= 4 + 12 + 9
= 25
Step 4: Compare
Left side = 25
Right side = 25
✓ Both sides are equal
Answer: (a + b)² = a² + 2ab + b² is verified. For a = 2, b = 3: both sides equal 25
Q4: Multiply: (2x + 3)(x - 2)
We multiply two binomials using the distributive property.
Step 1: Use the distributive property
(2x + 3)(x - 2) = 2x(x - 2) + 3(x - 2)
Step 2: Distribute 2x
2x(x - 2) = 2x² - 4x
Step 3: Distribute 3
3(x - 2) = 3x - 6
Step 4: Combine like terms
(2x + 3)(x - 2) = 2x² - 4x + 3x - 6
= 2x² - x - 6
Step 5: Verify using FOIL
First: 2x × x = 2x²
Outer: 2x × (-2) = -4x
Inner: 3 × x = 3x
Last: 3 × (-2) = -6
Result: 2x² - 4x + 3x - 6 = 2x² - x - 6 ✓
Answer: (2x + 3)(x - 2) = 2x² - x - 6
Q5: Use the identity (a - b)² = a² - 2ab + b² to find (5 - 3)²
We apply the algebraic identity (a - b)² = a² - 2ab + b².
Step 1: Identify a and b
a = 5
b = 3
Step 2: Apply the identity
(a - b)² = a² - 2ab + b²
(5 - 3)² = 5² - 2(5)(3) + 3²
Step 3: Calculate each term
5² = 25
2(5)(3) = 30
3² = 9
Step 4: Substitute
(5 - 3)² = 25 - 30 + 9 = 4
Step 5: Verify by direct calculation
(5 - 3)² = (2)² = 4 ✓
Answer: Using the identity (a - b)² = a² - 2ab + b², we get (5 - 3)² = 25 - 30 + 9 = 4
Q6: Expand: -2(3x - 4y)
We use the distributive property with a negative coefficient.
Step 1: Apply the distributive property
-2(3x - 4y) = -2(3x) - (-2)(4y)
= -2(3x) + 2(4y)
Step 2: Multiply
-2(3x) = -6x
2(4y) = 8y
Step 3: Combine
-2(3x - 4y) = -6x + 8y
Step 4: Verify by substituting a value, say x = 1, y = 1
Left side: -2(3(1) - 4(1)) = -2(3 - 4) = -2(-1) = 2
Right side: -6(1) + 8(1) = -6 + 8 = 2 ✓
Answer: -2(3x - 4y) = -6x + 8y
Showing 6 of 8 questions. Visit the full page for complete solutions.
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