question on proving a certain elliptic curve has rank 0

[American Citizen <website.reader3@gmail.com>]

Hello:

According to GP-Pari the elliptic curve (1) has rank = 0.

(1)   y^2 = x^3 + 4*x^2 + 8*x + 8

This curve has torsion 2Z with the torsion point [-2,0]

How can I prove that the curve absolutely has rank = 0?

Randall