Question

como resolver x=√x-1+3

Answer 1

x = √x-1+3
x² = (√x-1+3)²
x² = x - 1 + 3
x² - x + 1 - 3 = 0
x² - x - 2 = 0
Δ= b² - 4ac
Δ= (-1)² - 4·1·(-2)
Δ= 1 + 8
Δ= 9
x₁ = -b + √Δ/2a               x₂ = -b - √Δ/2a
x₁ = -(-1) + √9/2·1          x₂ = -(-1) - √9/2·1
x₁ = 1 + 3/2                    x₂ = 1 - 3/2
x₁ = 4/2                          x₂ = -2/2
x₁ = 2                             x₂ = -1

S={2;-1}