Question

Question #d1dec

Answer 1

Write a system of equations with respect to `a` and `k`.

`{(-20 = a(-2 - 1)^2 + k), (4 = a(2 - 1)^2 + k):}`

Solve equation 1 for `k`.

`-20 = 9a + k -> k = -20 - 9a`

`4 = a - 20 - 9a`

`4 + 20 = -8a`

`24 = -8a`

`a = -3`

`k = -20 - 9a`

`k = -20 - 9(-3)`

`k = 7`

So, the vertex has coordinates of `(1, 7)`.

Hopefully this helps!