Question

assume that y varies inversly with the square of x then solve when x is 5, y is 4/5 find y when x is 8

Answer 1

since y varies inversly with the square of x, it can be written like this

`y=(k)/(x^2)`

since y=4/5 when x=5, find k

`(4)/(5)=(k)/((5^2))`

clear the equation for k

`\begin{gathered} (4)/(5)(5^2)=k \\ 4\cdot5=k \\ 20=k \end{gathered}`

now that you have found k, use it to find y when x=8