Question

If f(x) varies inversely with x and f(x) = 5 when x = 4, find the value of f(x) when x = 8

2.5
4
6.5
8

Answer 1

direct variation maeans
\[f(x)=kx\] for some \(k\)

\(f(x)=5\) when \(x=4\) is a silly way of saying
\[f(4)=5\]

Answer 2

okay I gotcha thanks to much

Answer 3

that means \[f(4)=k\times 4=5\] and you can solve that for \(k\)

Answer 4

you good from there? you should get
\[k=\frac{5}{4}\]

Answer 5

yes im good thnaks

Answer 6

yw