1.
$\begin{align*}
{{23x}\over{24}}+{{9}\over{8}} &= {{5x}\over{6}}+{{4}\over{3}} && |\cdot 24\\
23x+27 &= 20x+32 && |-\left(20x+27\right)\\
3x &= 5 && |:3\\
x &= {{5}\over{3}}
\end{align*}$
2.
$\begin{align*}
{{17x}\over{9}}+{{7}\over{3}} &= {{4x}\over{3}}+{{28}\over{9}} && |\cdot 9\\
17x+21 &= 12x+28 && |-\left(12x+21\right)\\
5x &= 7 && |:5\\
x &= {{7}\over{5}}
\end{align*}$
3.
$\begin{align*}
{{17x}\over{8}}+{{5}\over{8}} &= {{7x}\over{4}}+{{5}\over{4}} && |\cdot 8\\
17x+5 &= 14x+10 && |-\left(14x+5\right)\\
3x &= 5 && |:3\\
x &= {{5}\over{3}}
\end{align*}$