Jawab:

Penjelasan dengan langkah-langkah:

1. x² + x - 3 = 0

x₁,₂ = {-1 ± √(1² - 4 (1) (-3))}/(2(1))

x₁,₂ = {-1 ± √(1 + 12)}/2

x₁,₂ = {-1 ± √13}/2

x₁ = {-1 + √13}/2

x₂ = {-1 - √13}/2

2. 2x² - 4x - 16 = 0

x₁,₂ = {-(-4) ± √((-4)² - 4 (2) (-16))}/(2(2))

x₁,₂ = {4 ± √(16 + 128)}/4

x₁,₂ = {4 ± √144}/4

x₁,₂ = {4 ± 12}/4

x₁ = {4 + 12}/4 = 4

x₂ = {4 - 12}/4 = -2

3. -5x² + 40x = 0

-x (5x - 40) = 0

x₁ = 0

5x - 40 = 0

5x = 40

x₂ = 40/5 = 8

4. -3x² + 8x - 1 = 0

x₁,₂ = {-8 ± √(8² - 4 (-3) (-1))}/(2(-3))

x₁,₂ = {-8 ± √(64 - 12)}/(-6)

x₁,₂ = {-8 ± √52}/(-6)

x₁ = {-8 + √52}/(-6) = {-8 + 2√13}/(-6) = {4 - √13}/3

x₂ = {-8 - √52}/(-6) = {-8 - 2√13}/(-6) = {4 + √13}/3

5. 4x² + 11x - 7 = 0​

x₁,₂ = {-11 ± √(11² - 4 (4) (-7))}/(2(4))

x₁,₂ = {-11 ± √(121 + 112)}/(8)

x₁,₂ = {-11 ± √233}/(8)

x₁ =  {-11 + √233}/(8)

x₂ =  {-11 - √233}/(8)