Answer:
y = (-7/3)(x - 9)
Explanation:
(12, - 7)
y = a(x - h)^2
-7 = a(12 - h)^2
- 7 = a(144 - 24x + h^2)
(9,0)
0 = a(x - h)^2
0 = a(9 - h)^2
0 = a(81 - 18h + h^2)
From (9,0) we can conclude that
a = 0
or
(9 - h)^2 = 0
Let's try the second possibility.
Take the square root of both sides.
9 - h = sqrt(0)
Add h to both sides
9 - h = 0
h = 9
So now what we have is
y = a(x - 9)
Use the first equation to get a
-7 = a(12 - 9)
-7 = a(3)
-7/3 = a
Answer
y = (-7/3)(x - 9)