For $y = {\log _a}x$ to be defined $'a'$ must be
Any positive real number
Any number
$ \ge e$
Any positive real number $ \ne 1$
${\log _4}18$ is
${\log _7}{\log _7}\sqrt {7(\sqrt {7\sqrt 7 } )} = $
Let $\left(x_0, y_0\right)$ be the solution of the following equations $(2 x)^{\ln 2} =(3 y)^{\ln 3}$ $3^{\ln x} =2^{\ln y}$ . Then $x_0$ is
If ${\log _{10}}x + {\log _{10}}\,y = 2$ then the smallest possible value of $(x + y)$ is
If $a, b, c$ are distinct positive numbers, each different from $1$, such that $[{\log _b}a{\log _c}a - {\log _a}a] + [{\log _a}b{\log _c}b - {\log _b}b]$ $ + [{\log _a}c{\log _b}c - {\log _c}c] = 0,$ then $abc =$