In each case, solve for x using square root property :
Question 1 :
x2 = 25
Question 2 :
x2 - 6 = 3
Question 3 :
2x2 + 5 = 5
Question 4 :
2x2 - 98 = 0
Question 5 :
32x2 = 2
Question 6 :
x2 - 3 = 14
Question 7 :
5x2 - 3 = 497
Question 8 :
(2x2 + 1)/3 = 29
Question 9 :
(x + ¼)2 - ¹⁄₁₆ = 0
Question 10 :
7x2 + 5 = 2280
Question 11 :
x2 + 4 = 0
Question 12 :
5 - 2x2 = -93
Question 13 :
5 - 3x2 = 80
Question 14 :
x2 + 8x + 16 = 0
Question 15 :
x2 - 12x + 11 = 0
1. Answer :
x2 = 25
Take square root on both sides.
√x2 = ±√25
x = ±√(5 ⋅ 5)
x = ±5
x = -5 or x = 5
2. Answer :
x2 - 6 = 3
Add 6 to both sides.
x2 = 9
Take square root on both sides.
√x2 = ±√9
x = ±3
x = -3 or x = 3
3. Answer :
2x2 + 5 = 5
Subtract 5 from both sides.
2x2 = 0
Divide both sides by 2.
x2 = 0
Take square root on both sides.
√x2 = ±√0
x = 0
4. Answer :
2x2 - 98 = 0
Add 98 to both sides.
2x2 = 98
Divide both sides by 2.
x2 = 49
Take square root on both sides.
√x2 = ±√49
x = ±√(7 ⋅ 7)
x = ±7
x = -7 or x = 7
5. Answer :
32x2 = 2
Divide both sides by 32.
x2 = ²⁄₃₂
x2 = ¹⁄₁₆
Take square root on both sides.
√x2 = ±√¹⁄₁₆
x = ±√(¼ ⋅ ¼)
x = ±¼
x = ⁻¹⁄₄ or x = ¼
6. Answer :
x2 + 3 = 14
Subtract 3 from both sides.
x2 = 11
Take square root on both sides.
√x2 = ±√11
x = ±√11
x = -√11 or x = √11
7. Answer :
5x2 - 3 = 497
Add 3 to both sides.
5x2 = 500
Divide both sides by 5.
x2 = 100
Take square root on both sides.
√x2 = ±√100
x = ±√(10 ⋅ 10)
x = ±10
x = -10 or x = 10
8. Answer :
(2x2 + 1)/5 = 11
Multiply both sides by 5.
2x2 + 1 = 55
Subtract 1 from both sides.
2x2 = 54
Divide both sides by 2.
x2 = 27
Take square root on both sides.
√x2 = ±√27
x = ±√(3 ⋅ 3 ⋅ 3)
x = ±3√3
x = -3√3 or x = 3√3
9. Answer :
(x + ¼)2 - ¹⁄₁₆ = 0
Add to ¹⁄₁₆ both sides.
(x + ¼)2 = ¹⁄₁₆
Take square root on both sides.
√(x + ¼)2 = ±√¹⁄₁₆
x + ¼ = ±√(¼ ⋅ ¼)
x + ¼ = ±¼
x + ¼ = ±¼
x + ¼ = ⁻¼ or x + ¼ = ¼
x + ¼ = ⁻¹⁄₄ x = ⁻¹⁄₄ ⁻ ¼ x = ⁻²⁄₄ x = ⁻¹⁄₂ |
x + ¼ = ¹⁄₄ x = ¹⁄₄ ⁻ ¼ x = 0 |
10. Answer :
7x2 + 5 = 2280
Subtract 5 from both sides.
7x2 = 2275
Divide both sides by 7.
x2 = 325
Take square root on both sides.
√x2 = ±√325
x = ±√(5 ⋅ 5 ⋅ 13)
x = ±5√13
x = -5√13 or x = 5√13
11. Answer :
x2 + 4 = 0
Subtract 8 from both sides.
x2 = -4
Take square root on both sides.
√x2 = ±√-4
x = ±√(-1 ⋅ 4)
x = ±√(i2 ⋅ 2 ⋅ 2)
x = ±2i
x = -2i or x = 2i
12. Answer :
5 - 2x2 = -93
Subtract 5 from both sides.
-2x2 = -98
Divide both sides by -2.
x2 = 49
Take square root on both sides.
√x2 = ±√49
x = ±√(7 ⋅ 7)
x = ±7
x = -7 or x = 7
13. Answer :
5 - 3x2 = 80
Subtract 5 from both sides.
-3x2 = 75
Divide both sides by -3.
x2 = -25
Take square root on both sides.
√x2 = ±√-25
x = ±√(-1 ⋅ 25)
x = ±√(-1 ⋅ 5 ⋅ 5)
x = ±√(i2 ⋅ 5 ⋅ 5)
x = ±5i
x = -5i or x = 5i
14. Answer :
x2 + 8x + 16 = 0
Rewrite x2 + 8x + 16 in the form of a2 + 2ab + b2.
x2 + 2(x)(4) + 42 = 0
We can use the algebraic identity (a + b)2 = a2 + 2ab + b2 to write the expression on the left side in terms of square of a binomial.
(x + 4)2 = 0
Take square root on both sides.
√(x + 4)2 = ±√0
x + 4 = 0
x = -4
15. Answer :
x2 - 12x + 11 = 0
Rewrite x2 - 12x + 61 in the form of a2 - 2ab + b2.
x2 - 2(x)(6) + 11 = 0
x2 - 2(x)(6) + 62 - 62 + 11 = 0
x2 - 2(x)(6) + 62 - 36 + 11 = 0
x2 - 2(x)(6) + 62 - 25 = 0
We can use the algebraic identity (a - b)2 = a2 - 2ab + b2 to write the expression on the left side in terms of square of a binomial.
(x - 6)2 - 25 = 0
Add 25 to both sides.
(x - 6)2 = 25
Take square root on both sides.
√(x - 6)2 = ±√25
x - 6 = ±√(5 ⋅ 5)
x - 6 = ±5
x - 6 = -5 x = 1 |
x - 6 = 5 x = 11 |
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