If $\frac{1}{\log_3 \pi} + \frac{1}{\log_4 \pi} > x$,then $x =$ ?

Let $a, b, c$ be real numbers, each greater than $1$, such that $\frac{2}{3} \log _{b} a+\frac{3}{5} \log _{c} b+\frac{5}{2} \log _{a} c=3$. If the value of $b$ is $9$, then the value of $a$ must be

If $\frac{1}{2} \le \log_{0.1} x \le 2$,then:

If $x = \log_{5}(1000)$ and $y = \log_{7}(2058)$,then:

If $\log_{10} 2 = 0.30103$ and $\log_{10} 3 = 0.47712$,the number of digits in $3^{12} \times 2^8$ is

If ${x_n} > {x_{n - 1}} > ... > {x_2} > {x_1} > 1$,then the value of ${\log _{{x_1}}}{\log _{{x_2}}}{\log _{{x_3}}}.....{\log _{{x_n}}}({x_n}^{{x_{n - 1}}^{{.^{{.^{{.^{{x_1}}}}}}}}})$ is equal to