The equation y = ax describes the graph of a line. if the value of a is positive, the line:

a. goes up and to the right.
b. is horizontal.
c. is vertical.
d. goes down and to the right.

The cost varies directly with the number of tickets purchased. it costs $145 for 10 people to attend a concert. a. what is the constant of proportionality (k)? b. write the direct variation equation. c. home much does it cost for 8 people? d. graph this situation. be sure to label each axis and give the graph a title.