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

theorem Th94: :: REAL_2'75
  c <> 0 & d <> 0 & a * c = b * d implies a / d = b / c
proof
  assume that
A1: c<>0 and
A2: d<>0;
  assume a*c = b*d;
  then a=b*d/c by A1,Lm9;
  then a=d*(b/c) by Lm8;
  hence thesis by A2,Lm9;
end;
