Function to find equation of plane .
def equation_plane ( x1 , y1 , z1 , x2 , y2 , z2 , x3 , y3 , z3 ) : NEW_LINE INDENT a1 = x2 - x1 NEW_LINE b1 = y2 - y1 NEW_LINE c1 = z2 - z1 NEW_LINE a2 = x3 - x1 NEW_LINE b2 = y3 - y1 NEW_LINE c2 = z3 - z1 NEW_LINE a = b1 * c2 - b2 * c1 NEW_LINE b = a2 * c1 - a1 * c2 NEW_LINE c = a1 * b2 - b1 * a2 NEW_LINE d = ( - a * x1 - b * y1 - c * z1 ) NEW_LINE print " equation ▁ of ▁ plane ▁ is ▁ " , NEW_LINE print a , " x ▁ + " , NEW_LINE print b , " y ▁ + " , NEW_LINE print c , " z ▁ + " , NEW_LINE print d , " = ▁ 0 . " NEW_LINE DEDENT