Question 1182625
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I don't think the answer from the other tutor is what the question was asking for....<br>
The domain of a function is the set of values that the independent variable can take on; the range is the set of values that the dependent variable can take on.<br>
Rita's pay depends on the number of copies she sells, so her pay is the dependent variable and the number of copies she sells is the independent variable.<br>
So the domain in this problem is the possible numbers of copies she can sell.  She obviously can't sell a negative number of copies, so the least she can sell is 0; and she only has 140 copies, so the maximum number she can sell is 140.  So the set of values for the domain (the possible numbers of copies N she can sell) is 0 <= N <= 140, with the restriction that x is an integer.<br>
ANSWER: Set of values for domain: {0, 1, 2, ..., 139, 140}<br>
If she sells no copies, she still gets paid: {{{P(0)=20(0)+1800=1800}}}, so the minimum her pay can be is 1800.  If she sells all 140 copies, her pay is {{{P(140)=20(140)+1800=2800+1800=4600}}}, so her maximum pay is 4600.<br>
And of course she can only sell whole numbers of copies, so...<br>
ANSWER: Set of values for the range: {1800, 1820, 1840, ..., {{{cross(4400)}}} 4580, 4600}<br>