Question:

$\left(\frac{-3}{7}\right)^{-1}=?$

(a) $\frac{7}{3}$

(b) $\frac{-7}{3}$

(c) $\frac{3}{7}$

(d) none of these

Solution:

(b) $\frac{-7}{3}$

$\left(-\frac{3}{7}\right)^{-1} \Rightarrow$ Reciprocal of $\frac{-3}{7}$

The reciprocal of $\frac{-3}{7}$ is $\frac{7}{-3}$, i. e., $\frac{-7}{3}$