In functions, each x value has its own corresponding y value, this meaning that the x value cannot repeat, and if it does it is not considered a function
Looking at the graph, no x value repeat, thus the graph represents a function
So you need to find 15% of $27.38. To do this you can multiply 27.38 * .15 and get 4.107. Round to $4.11 and this is the tip. The total bill would be $31.49
