Question 1143295
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(a) Evaluate the given expression at x=40.  You can do that with pencil and paper (or perhaps mentally); or you can use a graphing calculator: graph the function and evaluate it at x=40.<br>
(b) Set the given expression equal to 19000 and solve for x.  That will be very ugly with pencil and paper; it's very simple using a graphing calculator: graph the given function and the constant function 19000 and find the point of intersection.<br>
Note the x value will not be an integer; you will have to round up to make sure the profit is at least $19000.<br>
Since you pretty much have to use a graphing calculator to answer the second question, you might as well use it for both parts.