Answer:
The correct answer is A.
Step-by-step explanation:
The area of a rectangle can be calculated using the following formula:
If we know that the area measures 
and one side of the figure measures 4.2 m, we can say that:
We isolate the side we don't know:
So I = 9 m
To know the perimter of a rectangle, we use the following formula:
Answer:
-85.9
Step-by-step explanation:
The maximum profit is the highest point on the curve at (3, 45), and since the y-value is the profit in hundreds of dollars, the maximum profit is $4500.
The shop is making a profit as long as the curve is above the x-axis, so this is over the given interval (0, 10).
The maximum profit is earned at x = 3, and the x-value is the money spent on advertising in hundreds of dollars, so this means that $300 was spent of advertising.
