For finding the z - intercept put x = 0 and y = 0
let z = - D / C ; rslt [ 0 ] = x ; rslt [ 1 ] = y ; rslt [ 2 ] = z ; return rslt ; } function equation_plane ( p , q , r ) { let x1 = p [ 0 ] ; let y1 = p [ 1 ] ; let z1 = p [ 2 ] ; let x2 = q [ 0 ] ; let y2 = q [ 1 ] ; let z2 = q [ 2 ] ; let x3 = r [ 0 ] ; let y3 = r [ 1 ] ; let z3 = r [ 2 ] ;