Let T be the plane −x+2y = 4. Find the shortest distance d from the point P0=(2, 2, 1) to T, and the point Q in T that is closest to P0. Use the square root symbol '√' where needed to give an exact value for your answer.

I know I have posted this many times but I don't know what to do.. please help

2 answers

google is your friend. Try searching for

distance from point to plane

for some helpful discussions. For example,

mathinsight.org/distance_point_plane

it's just an extension of the usual formula for the distance from a point to a line.
Is this the final answer
d=sqrt5
Q:
x=-30/7
y=-18/7
z=-8/7