Can a function have a y-value with more than one x value why or why not ?

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Sam is a waiter at a local restaurant where he earns wages of $5 per hour sam figures that he also eams about $3 in tips for each person he serves sam works 6 hours on a particular day. if n represents the number of people sam serves that day, which of the following functions could sam use to figure ehis total earings for the do o a. en) = 30 o b. en) = 5n+ 18

Amachine part consists of a half sphere and a cylinder, as shown in the figure. the total volume of the part is π cubic inches.