reserve x,y,z,w for ExtReal,
  r for Real;
reserve f,g for ExtReal;
reserve t for ExtReal;

theorem Th95:
  x is real implies x*(y+z) = x*y +x*z
proof
  assume
A1: x is real;
  per cases;
  suppose
    y is real & z is real;
    hence thesis by A1,Lm27;
  end;
  suppose
    y is not real or z is not real;
    hence thesis by A1,Lm28;
  end;
end;
