Question

Efectuati
1)- 3 pe 4 + 5 pe 6
2)5 pe 8 - 2
3)-3 pe 10 x ( - 15 pe 9)
4) 28 pe 12 - 35 pe 15
5) 2 pe 3 : ( -12)

Answer 1

$\displaystyle 1).- \frac{3}{4} + \frac{5}{6} =- \frac{9}{12} + \frac{10}{12} = \frac{1}{12} \\ \\ 2). \frac{5}{8} -2= \frac{5}{8} - \frac{16}{8} =- \frac{11}{8} \\ \\ 3).- \frac{3}{10} \cdot \left(\begin{}{ - \frac{15}{9} }&&\\&&\\&&\end{array}\right) = \frac{45}{90} = \frac{1}{2} \\ \\ 4). \frac{28}{12} - \frac{35}{15} = \frac{140}{60} - \frac{140}{60} =0 \\ \\ 5). \frac{2}{3} :(-12)= \frac{2}{3} \cdot \left(\begin{}{- \frac{1}{12} }&&\\&&\\&&\end{array}\right)=- \frac{2}{36} =- \frac{1}{18}$