Question

Write the equation of the quadratic function with roots -10 and -8 and a vertex at (-9, -3).

Answer 1

Satellite pretty much showed you the format for this

Answer 2

is it the same for all?

Answer 3

Pretty much

Answer 4

still stumped...O.o

Answer 5

but ok

Answer 6

Here's what you can do with this information.

If the quadratic has a root of x = k, then it has a factor of (x-k).
i.e. for roots x = -10 and x = -8, the quadratic has factors (x+10)(x+8).

There may still be an additional constant factor, a, so simplify
y = a(x+10)(x+8) to get it in the form, ax^2+bx+c.

With the additional information of a vertex at (-9, -3), then you can use the vertex form of the equation y=a(x-h)+k and put in your given information. The vertex is at (h, k), so
y = a(x+9)^2 - 3.
If you simplify that, you get y = ax^2 +18ax +81a -3.

Compare that with the other equation to solve for a.