Salutare!
(x + 2)² - 2 (x + 1) - 10 = 0
x² + 4x + 4 - 2x - 2 - 10 = 0
x² + 2x - 8 = 0
a = 1 ; b = 2 ; c = -8
Δ = b² - 4ac
Δ = 2² - 4 · 1 · (-8) = 4 + 32 = 36 = 6²
x₁,₂ = ( -b ± √Δ ) / 2a = ( -2 ± 6 ) / 2
x₁ = ( -2 + 6 ) / 2 = 4 / 2 = 2
x₂ = ( -2 - 6 ) / 2 = -8 / 2 = -4
S = { -4 ; 2 }
