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

theorem :: REAL_2'78
  b <> 0 implies a * c = a * b * (c / b)
proof
  assume
A1: b<>0;
  thus a*c =a*1*c .=a*(b*b")*c by A1,XCMPLX_0:def 7
    .=a*b*(b"*c)
    .=a*b*(c/b) by XCMPLX_0:def 9;
end;
