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

theorem :: IRRAT_1'5
  a / (b * c * (d / e)) = (e / c) * (a / (b * d))
proof
  thus a/(b*c*(d/e)) = a/(b*c*(d*e")) by XCMPLX_0:def 9
    .= a/(c*(b*d*e"))
    .= a/(c*((b*d)/e)) by XCMPLX_0:def 9
    .= a/((b*d)/(e/c)) by Th81
    .= (e/c)*(a/(b*d)) by Th81;
end;
