Question

If y varies directly as x and `y=28` and `x=18`, how do you find y when `x = 9`?

Answer 1

`y=14`

Explanation:

`"the initial statement is "ypropx`

`"to convert to an equation multiply by k the constant"`
`"of variation"`

`y=kx`

`"to find k use the given condition"`

`y=28" when "x=18`

`y=kxrArrk=y/x=28/18=14/9`

`"equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(y=14/9x)color(white)(2/2)|)))`

`"when "x=9" then"`

`y=14/cancel(9)xxcancel(9)=14`