Question

Determine whether the parabola y = −x2 + 15x + 8 opens up, down, left, or right.

Answer 1

when you have y=ax^2+.... its either up or down,

x=ay^2+... is either left or right

Answer 2

when `a` is positive the parabola opens up (or to the right )
when `a` is negative the parabola opens down (or to the left )