Two systems of rectangular axes have the same origin. If a plane cuts them at distances a, b, c and a1,b1,c1 from the origin, then
1a2+1b2−1c2+1a12−1b12−1c12=0
1a2−1b2−1c2+1a12−1b12−1c12=0
1a2+1b2+1c2−1a12−1b12−1c12=0
1a2+1b2+1c2+1a12+1b12+1c12=0
xa+yb+zc=1,xa1+yb1+zc1=1
Distance from (0,0,0)is same
11a2+1b2+1c2=11(a|)2+1(b|)2+1(c|)2