Question

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

Answer 1

Very similar to the other 2 questions you've had:
Since it has roots at -10 and -8, it will be of the form:
\[y=a(x+10)(x+8)\]
Where a is a number we need to find. Now, you can substitute x=-9 and y=-3 to solve for a.
Are you able to have a go at this yourself now?

Answer 2

-3=a(-9+10)(-9+8) ?

Answer 3

Yep, now simplify this and see what you get :)

Answer 4

-3=a(1)(-1)

Answer 5

?

Answer 6

Yep, so -3=-a and a=3.