Question

f(x) varies inversely with x and f(x) = –15 when x = 30. What is the inverse variation equation?
a) f(x)= -5/x
b) f(x)= -2/x
c) f(x)= -90/x
d) f(x)= -450/x

Answer 1

the equations are already in inverse form...

if you switch x and y...

x = a/y. Solve for y

xy = a

y = a/x

The form doesn't change!! So you can just plug x and y into those equations to see which one works.

Answer 2

so its d i believe? @piglet9

Answer 3

yes :)

Answer 4

thanks!