Answer:

The equation of a parabola with vertex at the origin and symmetric about the y-axis is x² = 4ay

The  point P(2,-3) passes through above parabola,

2² = 4a(-3)

4 = -12a

a = -1/3

The equation of a parabola is,

x² = 4. (-1/3)y

x² = -4/3 y

3x² = -4y