Question

How would I graph this function as a parabola:
f(x)= -2(x+9)^2

Answer 1

(y-0) = -2 (x + 9)^2
when x is big either + or -, y is big negative
so it opens down (sheds water)

It is symmetric about x = -9 and y is 0 there
so the vertex is at (-9,0)
well put in another point or two and you have it. for example if x = -10 you will get the same y as when x = -8 (symmetric about x = -9)
y = -2 (-1)^2 or y = -2(+1)^2
or y = -4
so
(-10,-4) and (-8,-4) etc