Which equation has a graph that is a parabola with a vertex at (–1, –1)?
y = (x – 1)2 + 1
y = (x – 1)2 – 1
y = (x + 1)2 + 1
y = (x + 1)2 – 1

The vertex form of the equation for a parabola with vertex (h, k) can be written as ...

... y = (x -h)² +k

For h=k=-1, this is

... y = (x +1)² -1 . . . . matches the last choice

For completeness, we should say that a vertical scale factor may multiply the squared term. Here, there isn't one.

y = (x+1)^2 -1

c

step-by-step explanation: