(1,0 điểm) Thực hiện phép tính; a) ( − 3 4 + 2 7 ) : 4 9 + ( − 1 4 + 5 7 ) . ( 3 2 ) 2 ;b) ( − 3 4 ) 2 .0 , 16 − √ 16 25 : 16 9 + ( − 2024 ) 0 .
Hướng dẫn giải
a) \(\left( { - \frac{3}{4} + \frac{2}{7}} \right):\frac{4}{9} + \left( { - \frac{1}{4} + \frac{5}{7}} \right).{\left( {\frac{3}{2}} \right)^2}\) \( = \left( { - \frac{3}{4} + \frac{2}{7}} \right).\frac{9}{4} + \left( { - \frac{1}{4} + \frac{5}{7}} \right).\frac{9}{4}\) \( = \left( { - \frac{3}{4} + \frac{2}{7} - \frac{1}{4} + \frac{5}{7}} \right).\frac{9}{4}\) \( = \left[ {\left( { - \frac{3}{4} - \frac{1}{4}} \right) + \left( {\frac{5}{7} + \frac{2}{7}} \right)} \right].\frac{9}{4}\) \( = \left[ { - 1 + 1} \right].\frac{9}{4}\) \( = 0.\frac{9}{4}\) \( = 0.\) | b) \({\left( { - \frac{3}{4}} \right)^2}.0,16 - \sqrt {\frac{{16}}{{25}}} :\frac{{16}}{9} + {\left( { - 2024} \right)^0}\) \( = \frac{9}{{16}}.0,16 - \sqrt {{{\left( {\frac{4}{5}} \right)}^2}} .\frac{9}{{16}} + 1\) \( = \frac{9}{{16}}.\frac{4}{{25}} - \frac{4}{5}.\frac{9}{{16}} + 1\) \( = \left( {\frac{4}{{25}} - \frac{4}{5}} \right).\frac{9}{{16}} + 1\) \( = \left( {\frac{4}{{25}} - \frac{{20}}{{25}}} \right).\frac{9}{{16}} + 1\) \( = \frac{{ - 16}}{{25}}.\frac{9}{{16}} + 1\) \( = \frac{{ - 9}}{{25}} + 1\) \( = \frac{{16}}{{25}}.\) |