Реши уравнения

1. \(\dfrac{6}{11}:\dfrac{3}{22}=\dfrac{12}{17}:x\) .

2. \(\dfrac{21}{x+3}=\dfrac{7}{4}\) .

3. \(\dfrac{12}{13}=\dfrac{7,4-x}{2,6}\) .

4. \(48:35=\dfrac{1}{14}x:\dfrac{1}{16}\) .