Question

How can I write a quadratic function in vertex form?
vertex@(-1,-6) graph contains the point (0,-8)
vertex@(5,3) graph contains the points (4,6)
vertex@(-3,-6) graph contains the point (3,11)
x-inter. of graph is 8 and -4; y-inter. is -12

Answer 1

The general vertex form is:

y = a(x - h)^2 + k

where (h, k) is your vertex, so looking at the first one:

y = a(x - (-1))^2 + (-6) = a(x + 1) - 6

Substitute the other point to get the value for "a"

-8 = a(0 + 1) - 6 -> -8 = a - 6 -> a = -2

Substitute "a" back in along with h and k

y = -2(x + 1)^2 -6

Answer 2

Okay, I think i got it.

Answer 3

Good news!