37. Given points $M_{1}\left(x_{1}, y_{1}, z_{1}\right)$ and $M_{2}\left(x_{2}, y_{2}, z_{2}\right)$. Find the coordinates of the point lying on the $O x$ axis and equidistant from the given points.
37. The coordinates of the desired point have the form ( $x, 0,0$ ). Using the formula for the distance between points, we get the equation:

$$
\left(x_{1}-x\right)^{2}+y_{1}^{2}+z_{1}^{2}=\left(x_{2}-x\right)^{2}+y_{2}^{2}+z_{2}^{2}
$$

After expanding the brackets and transformations, we get:

$$
x=\frac{x_{2}^{2}-x_{1}^{2}+y_{2}^{2}-y_{1}^{2}+z_{2}^{2}-z_{1}^{2}}{2\left(x_{2}-x_{1}\right)}
$$