Question

If y varies inversely as x and y= 1/2 when x=8, find y when x=-4. ​

Answer 1

y = - 1

Explanation:

Given y varies inversely as x then the equation relating them is

y =
`(k)/(x)` ← k is the constant of variation

To find k use the condition y =
`(1)/(2)` when x = 8 , then

`(1)/(2)` =
`(k)/(8)` ( multiply both sides by 8 )

4 = k

y =
`(4)/(x)` ← equation of variation

When x = - 4 , then

y =
`(4)/(-4)` = - 1