** See attachment**

I'm having a hard time trying to figure out how to get outward unit normals for each surface of this shape. Here I have the question and the answer but still don't seem to be able to solve it..

I understand that to get a unit normal I divide by the length of n but I cant see how the answer is

S1: x = 0 and n (hat) = (-1,0,0)

S2: y = 0 and n (hat) = (0,-1,0)

S3: z = 0 and n (hat) = (0,0,-1)

is it..

for S1: nabla ( 3y + 2z -6 )

so is the unit normal

1/(sqrt(11))*(0,3,2) ????

If so then the answers I have are wrong!

Please can someone help. I have included the problem in the attachment.