The x-coord. of the vertex is halfway between the given zeros. Here, it'd be halfway between x=3 and x=9, which comes out to x = 6 (answer).
Answer:
x=6
Step-by-step explanation:
(x*3)+4=22
Subtracting 4 from both sides:
(x*3)=18
Dividing both sides by 3:
x=6
Hope this helps!
