Hi

The following question i am having problems with:

1) Find the equation of the plane normal to the vector 2i+j-3k

or

so

or

so or

book's answer says or

2) Find the equation of the plane which passes through the points (1,6,1), (3,5,2) and (3,2,1)

1,6,1), B3,5,2) and C3,2,1)" alt="A1,6,1), B3,5,2) and C3,2,1)" />

At plane (1,6,1)

4(1)+2(6)-6(1)=d

4+12-6=d

d=10

therefore equation is

however book's answer is

P.S