[tex] \frac{16+x}{x^{3} } + \frac{7-4x}{ x^{3} }
\\ 16+x+7-4x = 23-3x
\\ \frac{23 -3x}{ x^{3} } [/tex]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[tex] \frac{5}{t-1} +\frac{3}{t}
\\ \\ \frac{5t+(t-1)(3)}{(t-1)(t)}
\\ \\ \frac{5t+3t-3}{ t^{2}-t }
\\ \\ \frac{8t-3}{ t^{2}-t } [/tex]