Equation of the normal at a point on the parabolay2=36x , whose ordinate is three times its abcissacis-

Equation of the normal at 9m2,−18m on theparabola is y=mx−2×9m−9m3  where  −18m=3×9m2. i.e., m=0 or m=−2/3. For m=−2/3,  the equationof the normal is 2x+3y−44=0.