Thực hiện phép tính một cách hợp lí: k) ( 4/ 5 + − 9 /7 ) : 2 024 /2 025 + ( − 5/ 7 − − 6/ 5 ) : 2 024/ 2 025 .
Giải thích
k) \(\left( {\frac{4}{5} + \frac{{ - 9}}{7}} \right):\frac{{2024}}{{2025}} + \left( {\frac{{ - 5}}{7} - \frac{{ - 6}}{5}} \right):\frac{{2024}}{{2025}}\)
\[ = \left( {\frac{4}{5} + \frac{{ - 9}}{7} + \frac{{ - 5}}{7} - \frac{{ - 6}}{5}} \right):\frac{{2024}}{{2025}}\]
\[ = \left[ {\left( {\frac{4}{5} - \frac{{ - 6}}{5}} \right) + \left( {\frac{{ - 9}}{7} + \frac{{ - 5}}{7}} \right)} \right]:\frac{{2024}}{{2025}}\]
\[ = \left[ {\frac{{10}}{5} + \frac{{ - 14}}{7}} \right]:\frac{{2024}}{{2025}}\]
\[ = \left[ {2 + \left( { - 2} \right)} \right]:\frac{{2024}}{{2025}}\]
\[ = 0:\frac{{2024}}{{2025}} = 0.\]