(1,0 điểm) Thực hiện phép tính: a) 3 5 . 7 9 + 3 5 : 9 2 + ( − 3 5 ) 0 . b) √ 16 25 + ∣ ∣ − 4 5 ∣ ∣ . 1 3 − 2 3 : ( − 5 4 ) .
Hướng dẫn giải
a) \(\frac{3}{5}.\frac{7}{9} + \frac{3}{5}:\frac{9}{2} + {\left( { - \frac{3}{5}} \right)^0}\) \( = \frac{3}{5}.\frac{7}{9} + \frac{3}{5}.\frac{2}{9} + 1\) \( = \frac{3}{5}.\left( {\frac{7}{9} + \frac{2}{9}} \right) + 1\) \( = \frac{3}{5}.1 + 1\) \( = \frac{3}{5} + 1\) \( = \frac{8}{5}.\) | b) \(\sqrt {\frac{{16}}{{25}}} + \left| { - \frac{4}{5}} \right|.\frac{1}{3} - \frac{2}{3}:\left( { - \frac{5}{4}} \right)\) \( = \sqrt {{{\left( {\frac{4}{5}} \right)}^2}} + \frac{4}{5}.\frac{1}{3} - \frac{2}{3}.\left( { - \frac{4}{5}} \right)\) \( = \frac{4}{5} + \frac{4}{5}.\frac{1}{3} + \frac{2}{3}.\frac{4}{5}\) \( = \frac{4}{5}\left( {1 + \frac{1}{3} + \frac{2}{3}} \right)\) \( = \frac{4}{5}.\left( {1 + 1} \right)\) \( = \frac{4}{5}.2\) \( = \frac{8}{5}.\) |