Using the vertex of the quadratic function, it is found that:
a) The maximum number of customers in the store is at 12 P.M.
b) 75 customers are in the store at this time.
The number of customers in x hours after 7 AM is given by:

Which is a quadratic equation with coefficients 
Item a:
The maximum value, considering that a < 0, happens at:

Hence:

5 hours after 7 A.M, hence, the maximum number of customers in the store is at 12 P.M.
Item b:
The value is y(5), hence:

75 customers are in the store at this time.
A similar problem is given at brainly.com/question/24713268
Answer:
(-4,2)
Step-by-step explanation:
First we have to find a common multiple to use to add and find the system of equations. We need to eliminate one of the variables in order to solve.
Since 5 * 3 = 15, and 3 * -5 = 15, -15x and 15x will cancel each other out. Therefore x will be eliminated.
Before:
5x + 2y = -16
3x + 7y = 2
After:
15x + 6y = -48 <----------Now we solve for y
-15x + -35y = -10
+----------------------
-29y = -58
-29 -29
y = 2
Now what we do is we choose and equation and solve for x, since it is still unknown. Any equation is fine but I will choose the second one since it has easy numbers.
3x + 7y = 2
3x + 7(2) = 2
3x + 14 = 2
-14 -14
----------------------
3x = -12
3 3
x = -4
Therefore our final answer is (-4,2)
We are given the first term and the common ratio, this means they belong to a geometric series.
For the given series:

Each term of the geometric series is obtained by multiplying the previous term by common ratio.
So the next terms will be:
-4.5, -6.75, -10.125, -15.1875, -22.78125
The general formula for the G.P would be:

On plotting the series, the result will be like this:
Answer:
x = 11
y = 17
Step-by-step explanation:
We know that opposite angles (or vertical angles) are equal.
So
8x + 7 = 9x - 4
Subtract 8x from both sides of the equation
8x - 8x + 7 = 9x - 8x - 4
7 = x - 4
Add 4 to both sides of the equation
7 + 4 = x - 4 + 4
11 = x
Looking at the other 2 angles,
5y = 7y - 34
Subtract 7 y from both sides of the equation
5y - 7y = 7y - 7y - 34
-2y = -34
Divide both sides by -2
-2y/-2 = -34/-2
y = 17
We need to figure out how many more cans they need to bring. We figure this out by subtracting 403 from 1,000, which gives us 596 more cans. We now divide 596/28, to find how many each student would need to bring. This equals 21.3. You might want to mention that each student can't bring .3 of a can, so the answer could be 22 also.