Answer
$\quad y^{2}=-(x-1)$
Work Step by Step
Opens $left$. By Table 2,
$\begin{array}{|c|c|c|c|} \hline
{focus}&{directrix}&{equation}& ... opens\\ \hline
{(h-a,k)}&{x=h+a}&{(y-k)^{2}=-4a(x-h)} &left\\ \hline \end{array}$
Read from the graph: $\quad (h,k)=(1,0),$
so the equation has form $\quad y^{2}=-4a(x-1)$
Find $-4a$ by using the point on the graph (insert its coordinates into the equation)
$1^{2}=-4a(0-1)$
$1=4a$
$-4a=-1$
The equation is $\quad y^{2}=-(x-1)$