Question

Given that y varies directly with x, how do you write a direct variation equation that relates x and y for x = 5, y = 10?

Answer 1

If `y` varies directly with `x`, then
`y = mx` for some constant `m`

We are told that this relation holds for `(x,y) = (5,10)`
so
`10 = m*5`
`rarr m = 2`
and our direct variation equation is
`y = 5x`