Wow this one definitely tested me and was kind of tedious but I think I figured it out for you!
First times each term by the LCD which would be T(m)(n).
![( (1)/(m) (t)(m)(n)) + ( (1)/(n) (t)(m)(n)) = ( (1)/(t) (t)(m)(n))](https://img.qammunity.org/2019/formulas/mathematics/middle-school/rvl38ny4zj2w73x2v7uq23mo5s7hv0fpd3.png)
This cancels out the denominators and gives you a new equation.
![t(n) + t(m) = m(n)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ua5iezpftf7gakll8e3qb36vhtsp1wqs7i.png)
This is where it got a little confusing but I moved the terms with m to one side so that they could be factored out to isolate m.
![t(n) = m(n) - t(m)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/msipqkks30xrsy3jppgg0nhkqy0v3b6zpp.png)
Factoring out the m from the two terms gives you this equation.
![t(n) = m(n - t)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/7fp0rgfmdkvd4tgvgez1gkkkxoc81eudwk.png)
There is now only one term still connected to the m variable which can just be divided out. Giving you your final answer.
![(t(n))/(n - t) = m](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ig2zw13lz6ohg39n5hvk9io3g1r39sgrfr.png)
Hope this helped and was clear enough!
:)