S K Gupta and Anubhuti Gangal Solutions for Exercise 3: Mental Maths

Express in power notation ${\left(\frac{-2}{7}\right)}^{-3}\times {\left(\frac{-2}{7}\right)}^{-3}\times {\left(\frac{-2}{7}\right)}^{-3}$

Express ${\left(\frac{-3}{4}\right)}^{-2}$ as a rational number.

Express $\frac{-1}{216}$ as an exponent of a rational number.

Find the value of ${\left(\frac{1}{3}\right)}^{-1}+{\left(\frac{1}{5}\right)}^{-1}-{\left(\frac{1}{6}\right)}^{-1}$

Simplify ${\left(\frac{2}{3}\right)}^{-2}\times {\left(-\frac{7}{8}\right)}^0$

If $\frac{a}{b}={\left(\frac{2}{3}\right)}^{-3}\times {\left(\frac{5}{6}\right)}^0$, find the value of ${\left(\frac{a}{b}\right)}^{-3}$.

Find the value of $x$ if ${\left(\frac{5}{6}\right)}^7\times {\left(\frac{5}{6}\right)}^{-9}={\left(\frac{5}{6}\right)}^{2x}$