\(C=\left(\dfrac{6x+1}{x^2-6x}+\dfrac{6x-1}{x^2+6x}\right)\cdot\dfrac{x^2-36}{x^2+1}\)
\(C=\left[\dfrac{6x+1}{x\left(x-6\right)}+\dfrac{6x-1}{x\left(x+6\right)}\right]\cdot\dfrac{x^2-36}{x^2+1}\)
\(C=\dfrac{\left(x+6\right).\left(6x+1\right)+\left(x-6\right).\left(6x-1\right)}{x\left(x-6\right).\left(x+6\right)}\cdot\dfrac{x^2-36}{x+1}\)
\(C=\dfrac{6x^2+x+36x+6+6x^2-x-36x+6}{x\left(x-6\right).\left(x+6\right)}\cdot\dfrac{x^2-36}{x^2+1}\)
\(C=\dfrac{12x^2+12}{x\left(x-6\right).\left(x+6\right)}\cdot\dfrac{x^2-36}{x^2+1}\)
\(C=\dfrac{12\left(x^2+1\right)}{x\left(x-6\right).\left(x+6\right)}\cdot\dfrac{\left(x-6\right).\left(x+6\right)}{x^2+1}\)
\(\Rightarrow C=\dfrac{12}{x}\)
