Given:
f(x) = 70n - 400 : equation for monthly profit.
n = number of students enrolled in the guitar class.
70 refers to the amount charged per student.
400 is the fixed expense made by the instructor.
For the instructor to have a profit, the product of 70n must be more than 400.
400/70 = 5.7 or 6
There must be at least 6 students enrolled in class for the instructor to generate profit.
f(x) = 70(6) - 400 = 420 - 400 = 20
1000 = 70n - 400
1000 + 400 = 70n
1400 = 70n
1400/70 = n
20 = n
There must be 20 students enrolled in class for the instructor to earn 1000 in profit.
1000 = 70(20) - 400
1000 = 1400 - 400
1000 = 1000
Answer:
6x+9+2x
Step-by-step explanation:
8x+9
hope it helps uh
Let d represent number of days and n represent number of workers.
We have been given that when building a house, the number of days required to build varies inversely with with the number of workers.
We know that the equation 
represents the relation where y is inversely proportional to x and k is the constant of proportionality.
So our required equation would be 
Upon substituting our given values, we will get:
Since constant of proportionality is 665, so our equation would be 
.
To find the number of days it will take to build a similar house with 5 workers, we will substitute 
in our equation as:
Therefore, it will take 133 days for 5 workers to build a similar house.
11.k>-3(4r+3)/4r-5
12.k<(2x+2)/x+3
