how do i write an direct variation equation using coordinates like (5,1) for example

Answer 1

y = kx

Substitute 5 for x and 1 for y. Then solve for x.

1=k(5)

k = 1/5

y = (1/5)x

Answer 2

Direct variation is in the form

y = kx

For the numbers given

y = (1/5)x