Answer :
1. 3x² + 12x - 15 = 0
x = -(12) +/- √((12)² - 4(3)(-15))
2(3)
x = -12 +/- √(144 + 180)
6
x = -12 +/- √(324)
6
x = -12 +/- 18
6
x = -2 + 3
x = -2 + 3 x = -2 - 3
x = 1 x = -5
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2. 5x² + 11x + 2 = 0
x = -(11) +/- √((11)² - 4(5)(2))
2(5)
x = -11 +/- √(121 - 40)
10
x = -11 +/- √(81)
10
x = -11 +/- 9
10
x = -1¹/₁₀ + ⁹/₁₀
x = -1¹/₁₀ + ⁹/₁₀ x = -1¹/₁₀ - ⁹/₁₀
x = ¹/₅ x = -2
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3. 2x² - 11x + 14 = 0
x = -(-11) +/- √((-11)² - 4(2)(14))
2(3)
x = 11 +/- √(121 - 102)
6
x = 11 +/- √(9)
6
x = 11 +/- 3
6
x = 1⁵/₆ + ¹/₂
x = 1⁵/₆ + ¹/₂ x = 1⁵/₆ - ¹/₂
x = 2¹/₃ x = 1¹/₃
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4. 2x² - x - 15 = 0
x = -(-1) +/- √((-1)² - 4(2)(-15))
2(2)
x = 1 +/- √(1 + 120)
4
x = 1 +/- √(121)
4
x = 1 +/- 11
4
x = ¹/₄ + 2³/₄
x = ¹/₄ + 2³/₄ x = ¹/₄ - 2³/₄
x = 3 x = 2¹/₂
x = -(12) +/- √((12)² - 4(3)(-15))
2(3)
x = -12 +/- √(144 + 180)
6
x = -12 +/- √(324)
6
x = -12 +/- 18
6
x = -2 + 3
x = -2 + 3 x = -2 - 3
x = 1 x = -5
--------------------------------------------------------------------------------------------
2. 5x² + 11x + 2 = 0
x = -(11) +/- √((11)² - 4(5)(2))
2(5)
x = -11 +/- √(121 - 40)
10
x = -11 +/- √(81)
10
x = -11 +/- 9
10
x = -1¹/₁₀ + ⁹/₁₀
x = -1¹/₁₀ + ⁹/₁₀ x = -1¹/₁₀ - ⁹/₁₀
x = ¹/₅ x = -2
--------------------------------------------------------------------------------------------
3. 2x² - 11x + 14 = 0
x = -(-11) +/- √((-11)² - 4(2)(14))
2(3)
x = 11 +/- √(121 - 102)
6
x = 11 +/- √(9)
6
x = 11 +/- 3
6
x = 1⁵/₆ + ¹/₂
x = 1⁵/₆ + ¹/₂ x = 1⁵/₆ - ¹/₂
x = 2¹/₃ x = 1¹/₃
--------------------------------------------------------------------------------------------
4. 2x² - x - 15 = 0
x = -(-1) +/- √((-1)² - 4(2)(-15))
2(2)
x = 1 +/- √(1 + 120)
4
x = 1 +/- √(121)
4
x = 1 +/- 11
4
x = ¹/₄ + 2³/₄
x = ¹/₄ + 2³/₄ x = ¹/₄ - 2³/₄
x = 3 x = 2¹/₂
