Answer
unit vector n = $\frac{1}{7}$(6x+3y+2z) where x,y,z are the unit vectors in the Cartesian coordinate.
Work Step by Step
The method to find a unit vector perpendicular to a surface is divide the cross product of two sides of the surface (a and b in the diagram) with the modulus of the cross product (this is for normalizing the vector, so that its magnitude is one, i.e. a unit vector).
