Question

write the equation of a line parallel to the x-axis and is at a distance of 2 unit below x axis . represent this graphically also

Answer 1

parallel to x -axis , means equation of lines must be cut y axis perpendicularly
e.g general equation of line parallel of x -axis is y = a where a is constant which distance from x -axis above or below .

now, here question ask ,
2 unit below, means negative y -axis
e.g y -coordinate of line = -2 unit

hence, equation of line is ,
y = -2

Answer 2

A line parallel to the x-axis : Slope = 0 
It is at a distance of 2 unit below x axis : Passing from (0, - 2)

The equation of the line is :
y - y' = slope (x - x')
⇒y -(-2) = 0 ( x - 0)
⇒y = -2