A parabola has a vertex at (-1, 0) and opens down. What is the equation of the parabola?

Question

anonymous · Answer

the equation will be another one like the first two except you will have an negative sign thrown in before the first parenthesis to make it open down.

directrix · Answer

@Shannon20150  There are infintiely many parabolas which fit the posted description.

campbell_st · Answer

well the vertex form of the parabola is 

$$y = a(x - h)^2 + k$$

the vertex is (h, k) 

so and all you know about the value of a is that its negative... 

substituting the values for h = 1 and k = 0 and -a will cover all possible parabolas