The graph is correct. It is a straight line function through the two points (0,0) and (1,4). This indicates
x = 0 people buying tickets lead to y = 0 dollars in sales
x = 1 person buying a ticket leads to y = 4 dollars in sales
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You have the right idea for the domain; however, we include x = 0 and x = 200 as part of the interval. So you should say [0, 200] instead of (0,200)
The square brackets mean "include this endpoint". It is the same as writing
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The range would be [0, 800] for similar reasons as the domain. Again we include the endpoints. I changed the '4' to a '0' because 0 is the smallest y value possible, which happens when x = 0.
The range written as an inequality would look like this
(basically saying you can make anywhere between $0 and $800)