[tex]5kxb+6=7kx\qquad\text{subtract 6 from both sides}\\\\5kbx=7kx-6\qquad\text{subtract 7kx from both sides}\\\\5kbx-7kx=-6\\\\(5kb-7k)x=-6\qquad\text{divide both sides by}\ (5kb-7k)\neq0\\\\\boxed{x=\dfrac{-6}{5kb-7k}=\dfrac{6}{7k-5kb}}[/tex]