Question

The variables x and y vary inversely. Use the given values to write an equation relating x and y. x=5,y=-4

Answer 1

y =
`(-20)/(x)`

Explanation:

given x and y vary inversely then the equation relating them is

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

to find k , substitute x = 5, y = - 4 into the equation

- 4 =
`(k)/(5)` ( multiply both sides by 5 to clear the fraction )

5 × - 4 = 5 ×
`(k)/(5)` , then

- 20 = k

y =
`(-20)/(x)` ← equation relating x and y