firstly u can take the value of x=3 then put the value of x in equation..then u will get y = 0 so from this equation u get this(3,0)
then do same thing take value x = 6 and then u will get the value of y = -1 therefore u will get (6,-1)
Now plot these two points (3,0) and (6,-1) on graph..
Hope it helps u..!!