\(\dfrac{\left(6x+1\right)^2+\left(6x-1\right)^2-2}{\left(1+6x\right)\left(6x-1\right)}=\dfrac{\left(36x^2+12x+1\right)+\left(36x^2-12x+1\right)-2}{\left(6x+1\right)\left(6x-1\right)}=\dfrac{36^2+12x+1+36x^2-12x+1-2}{\left(6x+1\right)\left(6x-1\right)}=\dfrac{72x^2}{\left(6x+1\right)\left(6x-1\right)}\)