The cubic equation x³ + ax+ a = 0 has three roots x₁, x₂ and x₃ with x₁ ≤ x₂ ≤ x₃, where a is real and non zero, such that:

x₁²/ x₂ + x₂²/ x₃ + x₃²/ x₁ = 8

Determine x₁, x₂ and x₃