Question

What is the quadratic function that is created with roots -3 and 1 and a vertex at (-1, -8)?
Enter your answer as a function beginning with f(x).

Answer 1

the simplest form is
(x + 3)(x - 1)
- this gives roots -3 and 1
now we need to know if vertex is at (-1,-8)

Answer 2

can you give the f(x) of it?

Answer 3

Format using this sample answer:
f(x)=(3)(x^2-21x-19)

Answer 4

oh ok
f(x) = (x^2 + 2x - 3)

Answer 5

thank you.

Answer 6

to check if vertex is at (-1,-8) we write it in vertex form
(x^2 + 2x - 3) = (x+ 1)^2 -4

Answer 7

- thats not the right answer- sorry but I'm a bit rusty ate these - ill check this out

Answer 8

ok

Answer 9

right - to get vertex at (-1,8) the whole thing must be multiplied by 2
so its

2[(x + 1)^2 - 4]

so correct answer is

f(x) = (2)(x^2 + 2x - 3)

sorry about that

Answer 10

thank you that looks right!

Answer 11

yes - i've made sure using the math software wolfram alpha