Question

the value of x varies directly with the value of y and when x=3 y= -9 write an equation to represent the direct variation.​

Answer 1

y = - 3x

Explanation:

Given that x varies directly as y then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition y = - 9 when x = 3

k =
`(y)/(x)` =
`(-9)/(3)` = - 3

y = - 3x ← equation of variation