\[8x\text{\ \ \ }\]
\[при\ \ x = 1:\]
\[8 \cdot 1 = 8 - целое.\]
\[при\ x = \frac{1}{3}:\]
\[8 \cdot \frac{1}{3} = \frac{8}{3} = 2\frac{2}{3} - дробное.\]