Question

Find the multiplicative inverse of the following:
$-13$, $-\frac{13}{19}$ and $-\frac{5}{8}\times -\frac{3}{7}$

• A. $-\frac{1}{13};-\frac{19}{13};\frac{56}{15}$
• B. $-\frac{1}{13};\frac{19}{13};\frac{56}{15}$
• C. $\frac{1}{13};-\frac{19}{13};\frac{56}{15}$
• D. $\frac{1}{13};\frac{19}{13};\frac{56}{15}$

Answer 1

Answer: (A)

$-\frac{1}{13};-\frac{19}{13};\frac{56}{15}$

The multiplicative inverse of $-13$ is $(-13{)}^{-1}=\frac{1}{-13}$
The multiplicative inverse of $\frac{-13}{19}$ is ${\left(\begin{array}{c}\frac{-13}{19}\end{array}\right)}^{-1}=\frac{19}{-13}$.
$\frac{-5}{8}\times \frac{-3}{7}=\frac{-5\times -3}{8\times 7}=\frac{15}{56}$
The multiplicative inverse of $\frac{15}{56}$ is ${\left(\begin{array}{c}\frac{15}{56}\end{array}\right)}^{-1}=\frac{56}{15}$.