Question

Find points on the ellipsoid (x² + 4y² + z² = 9) where the tangent plane is parallel to the line with parametric equation (l(t) = t(-4,8,-2)).
a) (1, 1, 1)
b) (-1, -1, -1)
c) (2, -2, -2)
d) (0, 0, 3)