2x/(6x+7)=2/x. There's a common factor 2 that can be cancelled out from each side of the equation: x/(6x+7)=1/x. To get rid of the fractions we can cross-multiply by multiplying the left by x and the right by 6x+7: x^2=6x+7. This makes the quadratic: x^2-6x-7=0. The positive quantities on the right have become negative by being transferred over to the left. The quadratic factorises: (x+1)(x-7)=0, so the solution is x=-1 or 7. Substitute these values into the original equation to check them out: -2/(-6+7)=-2 and 14/(42+7)=2/7. Both correct!