Answer:
1. 6 students
2. 20 students
Explanation:
To find how many students the instructor must have to make a profit set f(x) = 0 and then solve for n. If it comes out as a decimal round up to the nearest whole number. If it comes out s a whole number add one. This is because 0 is not considered a profit it is considered breaking even. Also you can't have a fraction of a person. Also it is easier to solve for zero than for .01 which is the smallest profit you can make. Anyways...
0 = 70n - 400
0 + 400 = 70n - 400 + 400
400 = 70n
400/70 = 70n.70
5.7 = n
So, to make a profit the instructor needs to have 6 students.
To solve for how many students the instructor needs to have to make $1,000 per month, make f(x) = 1,000
1,000 = 70n - 400
1000 + 400 = 70n - 400 + 400
1400 = 70n
1400/70 = 70n/70
20 = n
The instructor needs to have 20 students to make a $1,000 profit.