Resposta:
Explicação passo a passo:
B) [tex]\left(-\frac{2}{5}\right)\left(-\frac{7}{8}\right)\left(\frac{10}{7}\right)[/tex]
[tex]=\frac{2}{5}\cdot \frac{7}{8}\cdot \frac{10}{7}[/tex]
[tex]=\frac{2\cdot \:7\cdot \:10}{5\cdot \:8\cdot \:7}[/tex]
[tex]=\frac{2\cdot \:10}{5\cdot \:8}[/tex]
[tex]=\frac{20}{40}[/tex]
[tex]=\frac{1}{2}[/tex]
C) [tex]\left(-\frac{2}{3}\right)\left(\frac{4}{6}\right)\left(-\frac{9}{8}\right)\left(\frac{1}{8}\right)[/tex]
[tex]=\frac{2}{3}\cdot \frac{4}{6}\cdot \frac{9}{8}\cdot \frac{1}{8}[/tex]
[tex]=\frac{2}{3}\cdot \frac{2}{3}\cdot \frac{9}{8}\cdot \frac{1}{8}[/tex]
[tex]=\frac{2\cdot \:2\cdot \:9\cdot \:1}{3\cdot \:3\cdot \:8\cdot \:8}[/tex]
[tex]=\frac{36}{3\cdot \:3\cdot \:8\cdot \:8}[/tex]
[tex]=\frac{36}{576}[/tex]
[tex]=\frac{1}{16}[/tex]
D) [tex]\left(-\frac{1}{5}\right)\begin{pmatrix}-2&3\end{pmatrix}[/tex]
[tex]=\begin{pmatrix}\left(-\frac{1}{5}\right)\left(-2\right)&\left(-\frac{1}{5}\right)\cdot \:3\end{pmatrix}[/tex]
[tex]=\begin{pmatrix}\frac{2}{5}&-\frac{3}{5}\end{pmatrix}[/tex]
E) [tex]\left(\frac{5}{8}\right)\left(1.2\right)[/tex]
[tex]=\frac{5}{8}\cdot \:1.2[/tex]
[tex]=\frac{5\cdot \:1.2}{8}[/tex]
[tex]=\frac{6}{8}[/tex]
[tex]=\frac{3}{4}[/tex]
[tex]=0.75[/tex]
F) [tex]\left(-\frac{6}{7}\right)\left(\frac{28}{18}\right)\left(-\frac{3}{7}\right)\begin{pmatrix}-0&4\end{pmatrix}[/tex]
[tex]=\begin{pmatrix}\left(-\frac{6}{7}\right)\frac{28}{18}\left(-\frac{3}{7}\right)\left(-0\right)&\left(-\frac{6}{7}\right)\frac{28}{18}\left(-\frac{3}{7}\right)\cdot \:4\end{pmatrix}[/tex]
[tex]=\begin{pmatrix}0&\frac{16}{7}\end{pmatrix}[/tex]
Espero ter ajudado, poderia marcar como melhor resposta? Agradeço :))