Of course, the relationship among the object distance, image distance, and focal length of the second lens is given by $\frac{1}{d_{2o}} + \frac{1}{d_{2i}} = \frac{1}{f_2}$ so $\frac{1}{d_{2i}} = \frac{1}{f_2} - \frac{1}{d_{2o}}$. Using this last equation for the second lens; the relationship for the object distance, image distance, and focal length of the first lens, $\frac{1}{d_{1o}} = \frac{1}{f_1} - \frac{1}{d_{1i}}$; the relationship between the image distance of the first lens $d_{1i}$ and the object distance of the second lens $d_{2o}$ answered in the previous question; and substituting these into the overall equation relating the original object distance $d_{1o}$ and final image distance $d_{2i}$ to the overall focal length of the two-lens system, i.e., $\frac{1}{d_{1o}} + \frac{1}{d_{2i}} = \frac{1}{f_{tot}}$; we can find a simple relationship between the focal lengths of the individual lenses of the system and the total focal length of that system (again, assuming the two lens are adjacent to each other so they nearly share the same optical plane). It is given by...
$\frac{1}{f_{tot}} = \frac{1}{f_1} + \frac{1}{f_2}$
$f_{tot} = f_1 + f_2$
$f_{tot} = f_1 * f_2$
$\frac{1}{f_{tot}} = \frac{1}{f_1} - \frac{1}{f_2}$