\(\frac{2}{7}< \frac{x}{3}< \frac{5}{4}\)
\(MSC=BCNN(7,3,4)=84\)
Ta quy đồng ra : \(\frac{2\cdot12}{84}< \frac{x\cdot28}{84}< \frac{5\cdot21}{84}\)
\(\Rightarrow\frac{24}{84}< \frac{28x}{84}< \frac{105}{84}\)
\(\Rightarrow24< 28x< 105\)
\(\Rightarrow x\in\left\{1;2;3\right\}\)
Vậy : ....
\(\frac{2}{7}< \frac{x}{3}< \frac{5}{4}\)
\(\Rightarrow\frac{24}{84}< \frac{28x}{84}< \frac{105}{84}\)
\(\Rightarrow24< 28x< 105\)
\(\Rightarrow x\ge1\)
\(\text{+) Nếu }x=1:24< 28.1< 105\left(TM\right)\)
\(\text{+) Nếu }x=2:24< 28.2< 105=24< 56< 105\left(TM\right)\)
\(\text{+) Nếu }x=3:24< 28.3< 105=24< 84< 105\left(TM\right)\)
\(\text{+) Nếu }x=4:24< 28.4< 105=24< 112< 105\left(KTM\right)\)
\(\text{Vậy x }\in\left\{1;2;3\right\}\)
