Tính: \(\,\,A = \frac{{ - 3}}{{13}} - \frac{7}{{17}} + \frac{{ - 5}}{{19}} + \frac{{ - 10}}{{13}} + \frac{{24}}{{17}} - \frac{{14}}{{19}}\)

* Hướng dẫn giải

\(\begin{array}{l}a)\,\,A = \frac{{ - 3}}{{13}} - \frac{7}{{17}} + \frac{{ - 5}}{{19}} + \frac{{ - 10}}{{13}} + \frac{{24}}{{17}} - \frac{{14}}{{19}}\,\,\\\,\,\,\,\,\,A = \frac{{ - 3}}{{13}} + \frac{{ - 7}}{{17}} + \frac{{ - 5}}{{19}} + \frac{{ - 10}}{{13}} + \frac{{24}}{{17}} - \frac{{14}}{{19}}\,\\\,\,\,\,\,\,A = \left( {\frac{{ - 3}}{{13}} + \frac{{ - 10}}{{13}}} \right) + \left( { - \frac{7}{{17}} + \frac{{24}}{{17}}} \right) + \left( {\frac{{ - 5}}{{19}} - \frac{{14}}{{19}}} \right)\\\,\,\,\,\,\,A = \frac{{ - 13}}{{13}} + \frac{{17}}{{17}} + \frac{{ - 19}}{{19}}\,\,\,\,\,\\\,\,\,\,\,\,A = ( - 1) + 1 + ( - 1)\,\,\,\,\,\,\,\,\,\,\,\,\\\,\,\,\,\,A = -1\,\,\,\,\end{array}\)

Chọn D