Odpowiedź :
x² - 10x + 21 = 0
Δ = 100 - 4 × 21
Δ = 16
√Δ = 4
x₁= (10 + 4) / 2
x₁= 7
x₂= (10 - 4) / 2
x₂= 3
Δ = 100 - 4 × 21
Δ = 16
√Δ = 4
x₁= (10 + 4) / 2
x₁= 7
x₂= (10 - 4) / 2
x₂= 3