 reserve a,b,c,x for Real;

theorem Cb2:
  AffineMap (-1/(c-b),c/(c-b)).c = 0
  proof
    AffineMap (-1/(c-b),c/(c-b)).c
         = (-1/(c-b))*c+c/(c-b) by FCONT_1:def 4
        .= ((-1)/(c-b))*c+c/(c-b) by XCMPLX_1:187
        .= (((-1)*c)/(c-b))+c/(c-b) by XCMPLX_1:74
        .= (-c+c)/(c-b) by XCMPLX_1:62
        .= 0;
    hence thesis;
  end;
