What is the equation of the axis of symmetry for the parabola y equals start fraction one over three end fraction left parenthesis x plus one right parenthesis squared minus three?

Y = (1/3) (x + 1) ^2 - 3

This is hk form of a parabola where hk is the vertex.

(-1,-3) is the vertex. The axis of symmetry is the vertical line that passes through the vertex of a parabola. The equation is x = - 1