Answer
The general equation of a parabola is [tex]y^2=4ax[/tex] which represents parabola opening along the positive x-axis and vertex at the origin.
Second equation of the parabola is [tex]y^2 = -4ax[/tex] which represents parabola opening in negative x-axis and vertex at origin.
3rd Equation of parabola is [tex]x^2 = 4ay[/tex] which represents parabola opening along the positive y-axis and vertex at the origin.
4th equation of the parabola is [tex]x^2 =- 4ay[/tex] which represents parabola opening along negative y-axis and vertex at the origin.
Hence, the 4th equation represents Equation 2 which is [tex]x^2 =- 4ay[/tex], and parabola opens down and has a negative y-intercept.
