Answer:

Step-by-step explanation:
There is a formula that can be used to find the x-value of the vertex of the parabola. This formula is 
We have the function 
From this function, we can find that

We can plug in our know values into the formula to get

Then we can plug in our x-value to find the y-value of the vertex

This means that the vertex would be 
Answer:
Option C 
Step-by-step explanation:
Let
x ----> the cost of the concert ticket
we know that
The total cost to be no more than $4 Above $80
so

Solve for x

The total cost to be no more than $4 below $80
so

Solve for x


therefore
The inequality that represent this problem is

<u><em>Verify</em></u>
<em>First solution (positive case</em>)


Solve for x
----> is ok
<em>Second solution (negative case)</em>

Multiply by -1 both sides


Solve for x

---> is ok
Remember that
is equivalent to 
Because is a absolute value
Your answer would be 46.50 because you would divide 31 in half (for the 50%) then add that to the 31. So 31+15.50= $46.50 hope this helps. If not let me know
The answer is 129 because the opposite corners of a quadrilateral has to equal 180°
The answer to your problem is C the third picture