I need help with these math questions :/

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)

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20

Which two undefined geometric terms always describe figures with no beginning or end?