Hi Prasad,
I think this is what you are looking for.
eqn = x^2 + (2*y^2) == 4;
sol = Solve[eqn, x]
sol /. y -> Range[0, 1.4, 0.2]
(* {{x -> {-2., -1.9799, -1.91833, -1.81108, -1.64924, -1.41421, -1.0583, -0.282843}},
{x -> {2., 1.9799, 1.91833, 1.81108, 1.64924, 1.41421, 1.0583, 0.282843}}} *)