Answer:
$1.12
Step-by-step explanation:
One way to solve this problem is through an algebraic equation. Set up the equation like this, 
. This equation works because 3.28 is subtracted from 10, which represents how much was spent in total. Then, this is equal to 6x, which represents the total cost of six keys.
So, to solve first subtract 3.28 from 10, this gives you 6.72. Then, divide both sides by 6. This equals 1.12, which is the cost of each key.
Answer: To solve this you need to use the vertex form of the equation of a parabola which is y=a(x−h)2+k , where (h,k) are the coordinates of the vertex.
Step-by-step explanation:
