\(\dfrac{8}{14}\) < \(\dfrac{15}{x}\) < \(\dfrac{8}{13}\)
\(\dfrac{8\times15}{14\times15}\) < \(\dfrac{15\times8}{x\times8}\) < \(\dfrac{8\times15}{13\times15}\)
14 \(\times\) 15 > \(x\times\) 8 > 13 \(\times\) 15
210 > \(x\) \(\times\) 8 > 195
\(\dfrac{210}{8}\) > \(x\) > \(\dfrac{195}{8}\)
26,25 > \(x\) > 24,375
Vì \(x\) là số tự nhiên nên \(x\) = 25