Thực hiện phép tính (tính hợp lí nếu có thể): a) [ ( − 2/3 )^ 9 ]^ 0 ; b) √ 25 /64 − ∣ ∣ − 7 /8 ∣ ∣ : 1/ 3 ;
Giải thích
a) \[{\left[ {{{\left( { - \frac{2}{3}} \right)}^9}} \right]^0} = {\left( { - \frac{2}{3}} \right)^{9.0}} = {\left( { - \frac{2}{3}} \right)^0} = 1\];
b) \(\sqrt {\frac{{25}}{{64}}} - \left| { - \frac{7}{8}} \right|:\frac{1}{3} = \frac{5}{8} - \frac{7}{8}.\frac{3}{1} = \frac{5}{8} - \frac{{21}}{8} = \frac{{ - 16}}{8} = - 2\);
c) \(\frac{1}{8}.\frac{4}{{11}} - \frac{1}{8}.\frac{8}{{11}} + \frac{{ - 12}}{{11}}.\frac{1}{8} = \frac{1}{8}.\left( {\frac{4}{{11}} - \frac{8}{{11}} + \frac{{ - 12}}{{11}}} \right)\)\( = \frac{1}{8}.\frac{{ - 16}}{{11}} = \frac{{ - 2}}{{11}}\).