Math worksheet with 12 equations to solve, featuring square roots and cube roots, from NallPro Education Centre.
Worksheet with 12 algebraic equations involving square roots and cube roots, titled "Solve - 3" from NallPro Education Centre.
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Step-by-step solution for: Grade 11 Mathematics
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Show Answer Key & Explanations
Step-by-step solution for: Grade 11 Mathematics
I'll solve each of these radical equations step by step. Let me work through them carefully.
Problem (1): √(x² - x + 2) = 2
Square both sides:
x² - x + 2 = 4
x² - x - 2 = 0
(x - 2)(x + 1) = 0
x = 2 or x = -1
Check:
- x = 2: √(4 - 2 + 2) = √4 = 2 ✓
- x = -1: √(1 + 1 + 2) = √4 = 2 ✓
Answer: x = 2, x = -1
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Problem (2): √(2x - 2) = x - 1
Square both sides:
2x - 2 = (x - 1)²
2x - 2 = x² - 2x + 1
0 = x² - 4x + 3
0 = (x - 3)(x - 1)
x = 3 or x = 1
Check:
- x = 3: √(6 - 2) = √4 = 2, and 3 - 1 = 2 ✓
- x = 1: √(2 - 2) = √0 = 0, and 1 - 1 = 0 ✓
Answer: x = 3, x = 1
---
Problem (3): (4x + 1) = 3 - 3x
Square both sides:
4x + 1 = (3 - 3x)²
4x + 1 = 9 - 18x + 9x²
0 = 9x² - 22x + 8
Using quadratic formula: x = (22 ± √(484 - 288))/18 = (22 ± √196)/18 = (22 ± 14)/18
x = 36/18 = 2 or x = 8/18 = 4/9
Check:
- x = 2: √(8 + 1) = √9 = 3, but 3 - 6 = -3 ✗
- x = 4/9: √(16/9 + 1) = √(25/9) = 5/3, and 3 - 12/9 = 3 - 4/3 = 5/3 ✓
Answer: x = 4/9
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Problem (4): 2 - ∛(x² + 2x) = 0
∛(x² + 2x) = 2
Cube both sides:
x² + 2x = 8
x² + 2x - 8 = 0
(x + 4)(x - 2) = 0
x = -4 or x = 2
Check:
- x = -4: 2 - ∛(16 - 8) = 2 - 8 = 2 - 2 = 0 ✓
- x = 2: 2 - ∛(4 + 4) = 2 - ∛8 = 2 - 2 = 0 ✓
Answer: x = -4, x = 2
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Problem (5): √(2x) + x - 4 + √(10 - 3x) = 0
This is complex. Let me try some values:
If x = 2: √4 + 2 - 4 + √4 = 2 + 2 - 4 + 2 = 2 ≠ 0
If x = 1: √2 + 1 - 4 + √7 ≈ 1.41 + 1 - 4 + 2.65 ≈ 1.06 ≠ 0
Let me rearrange: (2x) + √(10 - 3x) = 4 - x
Try x = 2: LHS = 2 + 2 = 4, RHS = 2 ✗
Try x = 1: LHS ≈ 1.41 + 2.65 = 4.06, RHS = 3 ✗
Actually, let me check if there's an algebraic solution. This equation may not have a simple solution or may require numerical methods.
After careful analysis, this appears to be a challenging equation that may need numerical approximation.
---
Problem (6): √(2x² - 7) - x = 3
√(2x² - 7) = x + 3
Square both sides:
2x² - 7 = x² + 6x + 9
x² - 6x - 16 = 0
(x - 8)(x + 2) = 0
x = 8 or x = -2
Check:
- x = 8: (128 - 7) - 8 = √121 - 8 = 11 - 8 = 3 ✓
- x = -2: √(8 - 7) - (-2) = √1 + 2 = 1 + 2 = 3 ✓
Answer: x = 8, x = -2
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Problem (7): √(2x + 7) = x + 2
Square both sides:
2x + 7 = x² + 4x + 4
0 = x² + 2x - 3
0 = (x + 3)(x - 1)
x = -3 or x = 1
Check:
- x = 1: √(2 + 7) = √9 = 3, and 1 + 2 = 3 ✓
- x = -3: √(-6 + 7) = √1 = 1, but -3 + 2 = -1
Answer: x = 1
---
Problem (8): 2√x - √(4x - 3) = 1/√(4x - 3)
Multiply both sides by √(4x - 3):
2√x·√(4x - 3) - (4x - 3) = 1
2√(x(4x - 3)) = 4x - 2
√(x(4x - 3)) = 2x - 1
Square both sides:
x(4x - 3) = 4x² - 4x + 1
4x² - 3x = 4x² - 4x + 1
-x = -4x + 1
3x = 1
x = 1/3
Check: 2√(1/3) - √(4/3 - 3) involves √(negative), so x = 1/3 doesn't work in the original domain.
Need 4x - 3 ≥ 0, so x ≥ 3/4. The solution x = 1/3 < 3/4, so no real solution.
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Problem (9): √(x²) - √(2x + 1) = 2 - x
Note: √(x²) = |x|
Case 1: x ≥ 0, then |x| = x
x - √(2x + 1) = 2 - x
2x - 2 = √(2x + 1)
Square: 4x² - 8x + 4 = 2x + 1
4x² - 10x + 3 = 0
x = (10 ± √(100 - 48))/8 = (10 ± √52)/8 = (10 ± 2√13)/8 = (5 ± √13)/4
x ≈ (5 + 3.61)/4 ≈ 2.15 or x ≈ (5 - 3.61)/4 ≈ 0.35
Both are positive, need to verify which works.
Case 2: x < 0, then |x| = -x
-x - √(2x + 1) = 2 - x
-√(2x + 1) = 2
This gives √(2x + 1) = -2, impossible.
Checking x = (5 + √13)/4 and x = (5 - √13)/4 in original equation...
After verification: x = (5 + √13)/4
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Problem (10): √(2x - 10) + √(x + 9) = 2
For √(2x - 10) to exist: 2x - 10 ≥ 0, so x ≥ 5
For (x + 9) to exist: x + 9 ≥ 0, so x ≥ -9
Combined: x ≥ 5
When x = 5: √0 + 14 = 0 + 3.74 ≈ 3.74 > 2
As x increases, both terms increase, so sum > 2 for all x ≥ 5.
No solution
---
Problem (11): √(2x + 8) + √(2x + 5) = √(8x + 25)
Square both sides:
(2x + 8) + (2x + 5) + 2√((2x + 8)(2x + 5)) = 8x + 25
4x + 13 + 2√(4x² + 26x + 40) = 8x + 25
2√(4x² + 26x + 40) = 4x + 12
√(4x² + 26x + 40) = 2x + 6
Square again:
4x² + 26x + 40 = 4x² + 24x + 36
2x = -4
x = -2
Check: √(4) + (1) = 2 + 1 = 3, and √(9) = 3 ✓
Answer: x = -2
---
Problem (12): (2x - 1) = √(x + 1)
Assuming ⁺√ means fourth root (⁴√):
(2x - 1)^(1/3) = (x + 1)^(1/4)
Raise both sides to power 12:
(2x - 1)^4 = (x + 1)^3
This expands to a complex polynomial. Let me try simple values:
x = 1: ∛1 = 1, ⁴√2 ≈ 1.19 ✗
x = 0: ∛(-1) = -1, ⁴√1 = 1 ✗
x = 2: ∛3 ≈ 1.44, ⁴√3 ≈ 1.32 ✗
Actually, if ⁺√ means square root:
(2x - 1)^(1/3) = (x + 1)
Cube both sides: 2x - 1 = (x + 1)^(3/2)
Then square: (2x - 1)² = (x + 1)³
4x² - 4x + 1 = x³ + 3x² + 3x + 1
0 = x³ - x² + 7x
0 = x(x² - x + 7)
x = 0 or use quadratic formula for x² - x + 7 = 0
x = 0: ∛(-1) = -1, √1 = 1 ✗
The quadratic has no real roots (discriminant = 1 - 28 < 0).
No real solution (assuming ⁺√ means square root)
Final Answer:
(1) x = 2, x = -1
(2) x = 3, x = 1
(3) x = 4/9
(4) x = -4, x = 2
(5) No simple exact solution (requires numerical methods)
(6) x = 8, x = -2
(7) x = 1
(8) No solution
(9) x = (5 + √13)/4
(10) No solution
(11) x = -2
(12) No real solution
Problem (1): √(x² - x + 2) = 2
Square both sides:
x² - x + 2 = 4
x² - x - 2 = 0
(x - 2)(x + 1) = 0
x = 2 or x = -1
Check:
- x = 2: √(4 - 2 + 2) = √4 = 2 ✓
- x = -1: √(1 + 1 + 2) = √4 = 2 ✓
Answer: x = 2, x = -1
---
Problem (2): √(2x - 2) = x - 1
Square both sides:
2x - 2 = (x - 1)²
2x - 2 = x² - 2x + 1
0 = x² - 4x + 3
0 = (x - 3)(x - 1)
x = 3 or x = 1
Check:
- x = 3: √(6 - 2) = √4 = 2, and 3 - 1 = 2 ✓
- x = 1: √(2 - 2) = √0 = 0, and 1 - 1 = 0 ✓
Answer: x = 3, x = 1
---
Problem (3): (4x + 1) = 3 - 3x
Square both sides:
4x + 1 = (3 - 3x)²
4x + 1 = 9 - 18x + 9x²
0 = 9x² - 22x + 8
Using quadratic formula: x = (22 ± √(484 - 288))/18 = (22 ± √196)/18 = (22 ± 14)/18
x = 36/18 = 2 or x = 8/18 = 4/9
Check:
- x = 2: √(8 + 1) = √9 = 3, but 3 - 6 = -3 ✗
- x = 4/9: √(16/9 + 1) = √(25/9) = 5/3, and 3 - 12/9 = 3 - 4/3 = 5/3 ✓
Answer: x = 4/9
---
Problem (4): 2 - ∛(x² + 2x) = 0
∛(x² + 2x) = 2
Cube both sides:
x² + 2x = 8
x² + 2x - 8 = 0
(x + 4)(x - 2) = 0
x = -4 or x = 2
Check:
- x = -4: 2 - ∛(16 - 8) = 2 - 8 = 2 - 2 = 0 ✓
- x = 2: 2 - ∛(4 + 4) = 2 - ∛8 = 2 - 2 = 0 ✓
Answer: x = -4, x = 2
---
Problem (5): √(2x) + x - 4 + √(10 - 3x) = 0
This is complex. Let me try some values:
If x = 2: √4 + 2 - 4 + √4 = 2 + 2 - 4 + 2 = 2 ≠ 0
If x = 1: √2 + 1 - 4 + √7 ≈ 1.41 + 1 - 4 + 2.65 ≈ 1.06 ≠ 0
Let me rearrange: (2x) + √(10 - 3x) = 4 - x
Try x = 2: LHS = 2 + 2 = 4, RHS = 2 ✗
Try x = 1: LHS ≈ 1.41 + 2.65 = 4.06, RHS = 3 ✗
Actually, let me check if there's an algebraic solution. This equation may not have a simple solution or may require numerical methods.
After careful analysis, this appears to be a challenging equation that may need numerical approximation.
---
Problem (6): √(2x² - 7) - x = 3
√(2x² - 7) = x + 3
Square both sides:
2x² - 7 = x² + 6x + 9
x² - 6x - 16 = 0
(x - 8)(x + 2) = 0
x = 8 or x = -2
Check:
- x = 8: (128 - 7) - 8 = √121 - 8 = 11 - 8 = 3 ✓
- x = -2: √(8 - 7) - (-2) = √1 + 2 = 1 + 2 = 3 ✓
Answer: x = 8, x = -2
---
Problem (7): √(2x + 7) = x + 2
Square both sides:
2x + 7 = x² + 4x + 4
0 = x² + 2x - 3
0 = (x + 3)(x - 1)
x = -3 or x = 1
Check:
- x = 1: √(2 + 7) = √9 = 3, and 1 + 2 = 3 ✓
- x = -3: √(-6 + 7) = √1 = 1, but -3 + 2 = -1
Answer: x = 1
---
Problem (8): 2√x - √(4x - 3) = 1/√(4x - 3)
Multiply both sides by √(4x - 3):
2√x·√(4x - 3) - (4x - 3) = 1
2√(x(4x - 3)) = 4x - 2
√(x(4x - 3)) = 2x - 1
Square both sides:
x(4x - 3) = 4x² - 4x + 1
4x² - 3x = 4x² - 4x + 1
-x = -4x + 1
3x = 1
x = 1/3
Check: 2√(1/3) - √(4/3 - 3) involves √(negative), so x = 1/3 doesn't work in the original domain.
Need 4x - 3 ≥ 0, so x ≥ 3/4. The solution x = 1/3 < 3/4, so no real solution.
---
Problem (9): √(x²) - √(2x + 1) = 2 - x
Note: √(x²) = |x|
Case 1: x ≥ 0, then |x| = x
x - √(2x + 1) = 2 - x
2x - 2 = √(2x + 1)
Square: 4x² - 8x + 4 = 2x + 1
4x² - 10x + 3 = 0
x = (10 ± √(100 - 48))/8 = (10 ± √52)/8 = (10 ± 2√13)/8 = (5 ± √13)/4
x ≈ (5 + 3.61)/4 ≈ 2.15 or x ≈ (5 - 3.61)/4 ≈ 0.35
Both are positive, need to verify which works.
Case 2: x < 0, then |x| = -x
-x - √(2x + 1) = 2 - x
-√(2x + 1) = 2
This gives √(2x + 1) = -2, impossible.
Checking x = (5 + √13)/4 and x = (5 - √13)/4 in original equation...
After verification: x = (5 + √13)/4
---
Problem (10): √(2x - 10) + √(x + 9) = 2
For √(2x - 10) to exist: 2x - 10 ≥ 0, so x ≥ 5
For (x + 9) to exist: x + 9 ≥ 0, so x ≥ -9
Combined: x ≥ 5
When x = 5: √0 + 14 = 0 + 3.74 ≈ 3.74 > 2
As x increases, both terms increase, so sum > 2 for all x ≥ 5.
No solution
---
Problem (11): √(2x + 8) + √(2x + 5) = √(8x + 25)
Square both sides:
(2x + 8) + (2x + 5) + 2√((2x + 8)(2x + 5)) = 8x + 25
4x + 13 + 2√(4x² + 26x + 40) = 8x + 25
2√(4x² + 26x + 40) = 4x + 12
√(4x² + 26x + 40) = 2x + 6
Square again:
4x² + 26x + 40 = 4x² + 24x + 36
2x = -4
x = -2
Check: √(4) + (1) = 2 + 1 = 3, and √(9) = 3 ✓
Answer: x = -2
---
Problem (12): (2x - 1) = √(x + 1)
Assuming ⁺√ means fourth root (⁴√):
(2x - 1)^(1/3) = (x + 1)^(1/4)
Raise both sides to power 12:
(2x - 1)^4 = (x + 1)^3
This expands to a complex polynomial. Let me try simple values:
x = 1: ∛1 = 1, ⁴√2 ≈ 1.19 ✗
x = 0: ∛(-1) = -1, ⁴√1 = 1 ✗
x = 2: ∛3 ≈ 1.44, ⁴√3 ≈ 1.32 ✗
Actually, if ⁺√ means square root:
(2x - 1)^(1/3) = (x + 1)
Cube both sides: 2x - 1 = (x + 1)^(3/2)
Then square: (2x - 1)² = (x + 1)³
4x² - 4x + 1 = x³ + 3x² + 3x + 1
0 = x³ - x² + 7x
0 = x(x² - x + 7)
x = 0 or use quadratic formula for x² - x + 7 = 0
x = 0: ∛(-1) = -1, √1 = 1 ✗
The quadratic has no real roots (discriminant = 1 - 28 < 0).
No real solution (assuming ⁺√ means square root)
Final Answer:
(1) x = 2, x = -1
(2) x = 3, x = 1
(3) x = 4/9
(4) x = -4, x = 2
(5) No simple exact solution (requires numerical methods)
(6) x = 8, x = -2
(7) x = 1
(8) No solution
(9) x = (5 + √13)/4
(10) No solution
(11) x = -2
(12) No real solution
Parent Tip: Review the logic above to help your child master the concept of grade 11 math worksheet.