a. What is the cost expression for the newspaper?
The cost would be the sum of fixed cost and the variable cost. The fixed cost
is 70 while the variable cost is 0.40 x, where x stands for the number of
copies made. That is:
Cost = 70 + 0.40 x
where x = number of copies made
b. What is the revenue expression for the newspaper?
The revenue would simply be the product of selling price and number of
copies sold or made, that is:
Revenue = 0.50 x
c. Put the cost and revenue expressions into an inequality that would represent
a successful newspaper.
To have a successful newspaper, the difference of revenue and cost must be
greater than 0, that is:
Revenue – Cost > 0
0.50 x – (70 + 0.40 x) > 0
d. How many copies should be sold to make a profit? Show all work! An answer
with no work will receive 0 points.
From the above equation, we solve for x.
0.50 x – (70 + 0.40 x) > 0
0.50 x – 70 – 0.40 x > 0
0.10 x > 70
x > 700
Number of copies made should be more than 700 copies
e. Now go back to your answer for d. On every line of your solution write what
property of math you would use to justify the transformation that
occurred.
0.50 x – (70 + 0.40 x) > 0 Distribution
property
0.50 x – 70 – 0.40 x > 0 Addition
property
0.10 x > 70 Addition
property
x > 700 Division
property
so we plug in the numbers (hypothenuse is always C in the equation) 
now we solve:
Exponents 
Subtract