1.
8x² + 2x - 1 = 0
Δ = b² - 4ac = 2² - 4·8·(-1) = 4 + 32 = 36
√Δ = √36 = 6
x₁ = (-2 - 6)/16 = -8/16 = -1/2
x₂ = (-2 + 6)/16 = 4/16 = 1/4
2.
-6x² + x + 1 = 0 |·(-1)
6x² - x - 1 = 0
Δ = (-1)² - 4·6·(-1) = 1 + 24 = 25
√Δ = √25 = 5
x₁ = (1 - 5)/12 = -4/12 = -1/3
x₂ = (1 + 5)/12 = 6/12 = 1/2
3.
3x² - 7x + 2 = 0
Δ = (-7)² - 4·3·2 = 49 - 24 = 25
√Δ = √25 = 5
x₁ = (7 - 5)/6 = 2/6 = 1/3
x₂ = (7 + 5)/6 = 12/6 = 2
