reserve a, b, c, d, e for Complex;

theorem Th188: :: REAL_1'39_2
  a / (- b) = -a / b
proof
  a/(-b)=(a*(-1))/((-b)*(-1)) by Lm10;
  then a/(-b)= (-a)/((-(-b))*1) .= -a/b by Lm17;
  hence thesis;
end;
