The distance of the point (1,0,−3) from the plane x−y−z=9 measured parallel to the line x−22=y+23=z−6−6
6
7
8
9
Let x−12=y−03=z+3−6=t (say) ⇒x=1+2t,y=3t,z=−3−6t Let P be a point in the plane x−y−z=9P=(3,3,−9)⇒AP=7