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:
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Step-by-step explanation:
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Comparing with A • 
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Hope this helps...
Good luck on your assignment...
Answer:
-1
Step-by-step explanation:
The first equation, make the y as the subject. y = 3 + 5x, then substitute y in the second equation and you will get the value of x. then, substitute the x in the first equation (y = 3 + 5x)