已知函数 f(x)=1a2x+1−ax3,a>1f\left( x\right) = \frac{1}{{a}^{2x} + 1} - a{x}^{3},a > 1f(x)=a2x+11−ax3,a>1 ,则关于 xxx 的不等式 f(x2)+f(5x−6)>1f\left( {x}^{2}\right) + f\left( {{5x} - 6}\right) > 1f(x2)+f(5x−6)>1 的解集是 ( )A. (−6,1)\left( {-6,1}\right)(−6,1) B. (2,3)\left( {2,3}\right)(2,3) C. (−∞,1)\left( {-\infty ,1}\right)(−∞,1) D. (2,+∞)\left( {2, + \infty }\right)(2,+∞)