What is the rule to these ordered pairs

The cost c, in dollars, for bananas depends on the weight w,in pounds, of the bananas. this situation is represented by the function rule c=0.5w (graph each function rule.tell whether the graph is continuous or discrete)

If f(x) and g(x) are inverse functions of each other, which of the following shows the graph of f(g(x)

What are the greatest common factor of 75 and 30