Nonlinear because the x is being multiplied to the y, and it cannot be written in standard form, and when graphed it’s a hyperbola
You can tell whether a relation is a function by plotting the numbers on a graph and applying the vertical line test. If no vertical line passing through the graph intersects it at more than one point, the relation is a function.
25-3=22 dollars left
then divide the amount of money left by the amount of candy bars
22/13= about 0.13 cents