Solve the following equations using operations.
\lfloor x-\dfrac{2}{7} \rfloor =3
\lfloor x-\dfrac{2}{3} \rfloor =7
\lfloor x-\dfrac{1}{5} \rfloor =12
\lfloor 3x-\dfrac{2}{9} \rfloor =2
\lfloor 5x-\dfrac{2}{7} \rfloor =4
\lfloor 7x+\dfrac{1}{2} \rfloor =-1
\lfloor x+\dfrac{2}{7} \rfloor =-5