How do you graph a parabola when your discriminant doesnt have a square root, therefor you cant go any farther?

I know that to graph a parabola you need a vertex, y-intercept, line of symmetry, and your x-intercepts ( solutions you find). well i could graph everything BUT the 2 solutions because in the equation 3x^2+6x-4=0 i ended up getting as final answers -6 + square root of 84 divided by 6 and -6 - square root of 84 divided by 6 because 84 doesn't have a square root. I don't know how to graph these x-intercepts because its cant simplify and isn't one number. Please Help!!!!!!