Question

The graph of which quadratic equation is shown below?

a u-shaped graph on a coordinate plane that is opening down and has a vertex of (−1, 9)

y = x2 + 2x − 8
y = x2 − 2x − 8
y = −x2 − 2x + 8
y = −x2 − 4x − 8

Answer 1

we can eliminate 2 answer choices since the question asks for the equations that open down

Answer 2

do you know how to find the vertex using the equation?