[tex][\frac{x}{10}]=[\frac{x}{8}]=^{not}r\\
Stim\ ca:\\
r\leq\frac{x}{8}\ \textless \ r+1\\
r\leq\frac{x}{10}\ \textless \ r+1\\
Daca\ inmultim\ a\ doua\ relatie\ cu\ -1\ obtinem:\\
-r-1\ \textless \ -\frac{x}{10}\leq-r\\
Prin\ adunarea\ celor\ doua\ relatii:\\
-1\ \textless \ \frac{x}{8}-\frac{x}{10}\ \textless \ 1\\
-1\ \textless \ \frac{x}{40}\ \textless \ 1|\cdot 40\\
-40\ \textless \ x\ \textless \ 40\Rightarrow \boxed{\bold{x\in (-40,40)}}[/tex]