Question

X la puterea a 2 +6x+5=0

Answer 1

Răspuns:

x₁ = -5 ; x₂ = -1

Explicație pas cu pas:

x²+6x+5 = 0  <=> x²+5x+x+5 = 0  <=>

Varianta 1:

x(x+5) + (x+5) = 0 <=> (x+5)·(x+1) = 0  => x₁ = -5 ; x₂ = -1

Varianta 2:

x²+6x+5 = 0  

a = 1 ; b = 6 ; c = 5

Δ = b²-4ac = 6²-4·1·5 = 36-20 = 16

√Δ = √16 = 4

x₁,₂ = (-b±√Δ)/2a = (-6±4)/2

x₁ = (-6-4)/2 = -10/2 => x₁ = -5

x₂ = (-6+4)/2 = -2/2 => x₂ = -1