C= -1 because when you add 38 to the other side you are left with -75c=75 then divide by -75 and you are left with -1
The vertex of the given modulus function is (3,-7).
Given information:
The given modulus function is,

It is required to find the vertex of the given function.
<h3>What is the vertex of a modulus function?</h3>
Modulus function is in the shape of V. The notch of V is the vertex of the function.
The given function can be defined as,

From the above function, it can be concluded that the vertex of the function should be (3,-7). Also shown in the attached image.
See the attached image.
Therefore, the vertex of the given modulus function is (3,-7).
For more details about modulus function, refer to the link:
brainly.com/question/18793028
C=300+1200x-100x. Find x if the total cost is 3,000
3,000 = 300 + 1200x -100x
3000 = 300 + 1100x
2700 = 1100x
2700÷1100=x
x=27/11
x = 2 5/11
Round to 3