1. Suppose y varies directly with x and, y=15 and x=5. Write a direct variation equation that relates x and y. What is the value of y when x=9?

I need a little help on how to figure out how to write this out. Any help will be appreciated. Thank you

2 answers

y=kx
so, y/x = k is constant.

You want y such that

y/9 = 15/5

You don't really need to know what k is.
Thank you for your help.