equation of a plane 1/4 distance form another plane?

Question

ok so here is the question. :
Compute the equation of the plane which lies one forth of the way from the plane
r * (2,-3,1) = 5
to the plane
r * (-6, 9, -3) = -1


I'm thinking its not too difficult of a problem but I havn't done math in over 3 yrs now.
This is what i have so far.
x + 1/4 (y - x) = 1/4y + 3/4x
now putting this into the plane equation, I get a little confused on how to subtract one plane from another.

Answer 1

r(2,-3,1)=23/6