Final answer:
The total cost of the online game can be calculated using the expression 15 + 10x, where x is the number of months played. If a player keeps the subscription for 15 months, the total cost will be $165.00.
Step-by-step explanation:
a) The expression for the total cost of the game is $15.00 (joining fee) plus $10.00 (monthly fee) multiplied by the number of months played. This can be represented as 15 + 10x, where x is the number of months played.
b) The variable x represents the number of months played.
c) The expression 15 + 10x is a linear polynomial because it has degree 1, and it represents a straight line on a graph.
d) If a player keeps the subscription for 15 months, we can plug in x = 15 into the expression. The total cost will be 15 + 10(15) = 15 + 150 = $165.00.
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