Question 13363
Equation of a line parallel to line ax+by+c= 0 is ax+by+k=0

So parallel line to x-3y=9 is x-3y+k = 0

But this line passes through (0,0)

So the point should satisfy the equation

0 - 3(0) + k = 0
k= 0
Line is x-3y=0