Observe the graph :
\The graph of the poarabola is vertically opens upward ,so the general form of the parabola equation is .
From the graph the vertex of the parabola is .
Substitute in
.
The parabola opens upward .so the value of is positive.
Consider the point on the parabola.
Substitute in
.
.
Substitute in
.
Therefore, the equation of the parabola is .
The equation of the parabola is .
The focus of the parabola is .
Substitute and
.
The focus of the parabola is .
The directrix of the parabola is .
Substitute and
.
The directrix of the parabola is .
The equation of the parabola is .
The focus of the parabola is .
The directrix of the parabola is .