Observe the graph :
\The graph of the poarabola is vertically opens upward, so the general form of the parabola equation is
.
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
.