Step-by-step explanation:
[tex]\longmapsto \rm \dfrac{5x}{7} - \dfrac{x}{14} = \dfrac{9}{7} \\ [/tex]
[tex]\longmapsto \rm \dfrac{10x + x}{14} = \dfrac{9}{7} \\ [/tex]
[tex]\longmapsto \rm \dfrac{11x}{14} = \dfrac{9}{7} \\ [/tex]
→ 11x(7) = 14(9)
→ 77x = 126
→ x = 126 ÷ 77
→ x = 1.63