We are asked to write the equation of the parabola with vertex at the origin and directrix x=11:

The equation of a parabola with vertex at the origin and focus at (a,0) is `y^2=4ax ` ; the parabola opens to the right if a>0 and to the left if a<0.

The vertex is the midpoint of the perpendicular segment drawn from the focus to the directrix.

Here the focus will be at (-11,0) so the equation we seek is `y^2=-44x `