The function f(x) varies inversely with x and f(x) = -15 when x = 30

what is the inverse variation equation

F(x) = k/x

f(30) = -15
⇒ k/30 = -15
⇒ k = 30 * -15 = -450

f(x) = -450/x

Hope it helps!

Okay so since we have all the variables, we can go ahead and make our formula. So our equation would look like z = (w/x) divided by y . This is because z would be the sum of the x miles divided by the cost of each mile (w). And then we would divide what we got in the parenthesis by y (friends).