Linear Inequalities — Class 11 Mathematics NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 11 Mathematics chapter "Linear Inequalities" — 7 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 11 Mathematics chapter "Linear Inequalities" — 7 important questions with detailed answers for CBSE board…
By Syllab.in · Updated
Key Questions Covered:
- Solve the linear inequality 3x - 5 > 7 and represent the solution on a number…
- Solve the compound inequality -3 ≤ 2x + 1 < 5.
- Solve the absolute value inequality |x - 3| ≤ 2.
- Solve the system of linear inequalities: 2x + y ≤ 8 x - y ≥ -2 x ≥ 0, y ≥ 0
- Solve the quadratic inequality x² - 5x + 6 > 0.
- Solve the inequality (x + 1)/(x - 2) > 0.
- + 1 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| Solve the linear inequality 3x - 5 > 7 and represent the … | ✓ Solved |
| Solve the compound inequality -3 ≤ 2x + 1 < 5. | ✓ Solved |
| Solve the absolute value inequality |x - 3| ≤ 2. | ✓ Solved |
| Solve the system of linear inequalities: 2x + y ≤ 8 x - y… | ✓ Solved |
| Solve the quadratic inequality x² - 5x + 6 > 0. | ✓ Solved |
| Solve the inequality (x + 1)/(x - 2) > 0. | ✓ Solved |
Showing 6 of 7 questions
Q1: Solve the linear inequality 3x - 5 > 7 and represent the solution on a number line.
Step 1: Isolate the variable term.
3x - 5 > 7
3x > 7 + 5
3x > 12
Step 2: Divide both sides by 3.
x > 12/3
x > 4
Step 3: Write the solution set.
Solution = {x ∈ ℝ : x > 4} or in interval notation: (4, ∞)
Step 4: Represent on a number line.
←────○────────────→
0 4 5 6 7
Open circle at 4, arrow pointing right to indicate all numbers greater than 4.
Step 5: Verify with test points.
Test x = 5: 3(5) - 5 = 15 - 5 = 10 > 7 ✓
Test x = 4: 3(4) - 5 = 12 -...
Q2: Solve the compound inequality -3 ≤ 2x + 1 < 5.
Step 1: Break into two separate inequalities.
-3 ≤ 2x + 1 AND 2x + 1 < 5
Step 2: Solve the left inequality -3 ≤ 2x + 1.
-3 ≤ 2x + 1
-3 - 1 ≤ 2x
-4 ≤ 2x
-2 ≤ x
Or: x ≥ -2
Step 3: Solve the right inequality 2x + 1 < 5.
2x + 1 < 5
2x < 5 - 1
2x < 4
x < 2
Step 4: Combine the solutions.
x ≥ -2 AND x < 2
Solution: -2 ≤ x < 2
Step 5: Write in interval notation.
[-2, 2)
Step 6: Verify with test points.
Test x = -2: -3 ≤ 2(-2) + 1 = -3 ≤ -3 ✓ and -3 < 5 ✓
Test x = 0: -3 ≤ ...
Q3: Solve the absolute value inequality |x - 3| ≤ 2.
Step 1: Recall the definition of absolute value inequality.
|A| ≤ B (where B ≥ 0) is equivalent to -B ≤ A ≤ B
Step 2: Apply the definition.
|x - 3| ≤ 2
-2 ≤ x - 3 ≤ 2
Step 3: Add 3 to all parts.
-2 + 3 ≤ x - 3 + 3 ≤ 2 + 3
1 ≤ x ≤ 5
Step 4: Write the solution set.
Solution: [1, 5]
Step 5: Verify with test points.
Test x = 1: |1 - 3| = |-2| = 2 ≤ 2 ✓
Test x = 3: |3 - 3| = 0 ≤ 2 ✓
Test x = 5: |5 - 3| = 2 ≤ 2 ✓
Test x = 0: |0 - 3| = 3 ≤ 2 ✗
Test x = 6: |6 - 3| = 3 ≤ 2 ✗
Final Answer: 1 ≤ x ≤ 5 ...
Q4: Solve the system of linear inequalities: 2x + y ≤ 8 x - y ≥ -2 x ≥ 0, y ≥ 0
Step 1: Identify the inequalities.
(1) 2x + y ≤ 8
(2) x - y ≥ -2, or x ≥ y - 2
(3) x ≥ 0 (non-negative x)
(4) y ≥ 0 (non-negative y)
Step 2: Find boundary lines by converting to equations.
Line 1: 2x + y = 8 ⟹ y = 8 - 2x
Line 2: x - y = -2 ⟹ y = x + 2
Line 3: x = 0 (y-axis)
Line 4: y = 0 (x-axis)
Step 3: Find key intersection points.
Intersection of 2x + y = 8 and x - y = -2:
2x + y = 8
x - y = -2
Adding: 3x = 6 ⟹ x = 2, y = 4
Point: (2, 4)
Intersection of 2x + y = 8 and x = 0:
2(0) + y = 8 ⟹...
Q5: Solve the quadratic inequality x² - 5x + 6 > 0.
Step 1: Factor the quadratic expression.
x² - 5x + 6 = (x - 2)(x - 3)
Step 2: Find the zeros (critical points).
(x - 2)(x - 3) = 0
x = 2 or x = 3
Step 3: Determine the sign of (x - 2)(x - 3) in each interval.
Test intervals: (-∞, 2), (2, 3), (3, ∞)
Test x = 0 (from interval (-∞, 2)):
(0 - 2)(0 - 3) = (-2)(-3) = 6 > 0 ✓
Test x = 2.5 (from interval (2, 3)):
(2.5 - 2)(2.5 - 3) = (0.5)(-0.5) = -0.25 < 0 ✗
Test x = 4 (from interval (3, ∞)):
(4 - 2)(4 - 3) = (2)(1) = 2 > 0 ✓
Step 4: Wri...
Q6: Solve the inequality (x + 1)/(x - 2) > 0.
Step 1: Find critical points where the expression equals zero or is undefined.
Numerator: x + 1 = 0 ⟹ x = -1
Denominator: x - 2 = 0 ⟹ x = 2 (undefined, asymptote)
Step 2: Create a sign chart with intervals.
Intervals: (-∞, -1), (-1, 2), (2, ∞)
Step 3: Test the sign in each interval.
Test x = -2 (from (-∞, -1)):
(-2 + 1) / (-2 - 2) = (-1) / (-4) = 1/4 > 0 ✓
Test x = 0 (from (-1, 2)):
(0 + 1) / (0 - 2) = 1 / (-2) = -1/2 < 0 ✗
Test x = 3 (from (2, ∞)):
(3 + 1) / (3 - 2) = 4 / 1 = 4 > 0...
Showing 6 of 7 questions. Visit the full page for complete solutions.
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