13*. What digits are denoted by the letters \(x, y\) and \(z\), if the product of the number \(\overline{x y}\) and the number \(x\) equals \(\overline{z z z}\)?
13. \(x=3, y=7, z=1\). Hint. Show that the number \(\overline{x y}\) is divisible by 37.