Find the equation of a line parallel to x-axis and passing through the origin.

Explanation

Let point A is on x-axis. Then coordinates of A are `(a,0,0)` where `a in R`.
The direction ratio of OA are `(a-0),0,0=a,0,0`
Equation of OA is :
`(x-0)/(a) = (y-0)/(0) = (z-0)/(0) rArr (x)/(1) = (y)/(0) = (z)/(0)`