The equation of a straight line in intercept-intercept form is `x/a+y/b=1` where a is the x-intercept and b is the y-intercept.

Rewrite the given line in this form.

x-3y=18

=> `x/18 - (3y)/18 = 1`

=> `x/18 - y/6 = 1`

This gives a = 18 and b = -6

For the line x-3y=18, the x-interceptt is 18 and the y-intercept is -6