a) \(\dfrac{1}{4}-\dfrac{2}{-3}+\dfrac{11}{8}\\ =\dfrac{6+16-33}{24}=-\dfrac{11}{24}\)
b) \(1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\\ =\dfrac{7}{5}.\dfrac{15}{49}-\dfrac{22}{15}:\dfrac{11}{5}\\ =\dfrac{3}{7}-\dfrac{2}{3}\\ =\dfrac{9-14}{21}=-\dfrac{5}{21}\)
a, \(\dfrac{1}{4}-\dfrac{2}{-3}-\dfrac{11}{8}.\)
\(=\dfrac{1}{4}+\dfrac{2}{3}+\dfrac{-11}{8}.\)
\(=\dfrac{6}{24}+\dfrac{16}{24}+\dfrac{33}{24}.\)
\(=\dfrac{6+16+\left(-33\right)}{24}.\)
\(=\dfrac{-11}{24}.\)
b, \(1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}.\)
\(=\dfrac{7}{5}.\dfrac{15}{49}-\left(\dfrac{12}{15}+\dfrac{10}{15}\right):\dfrac{11}{5}.\)
\(=\dfrac{3}{7}-\dfrac{22}{15}:\dfrac{11}{5}.\)
\(=\dfrac{3}{7}-\dfrac{22}{15}.\dfrac{5}{11}.\)
\(=\dfrac{3}{7}-\dfrac{22.5}{15.11}.\)
\(=\dfrac{3}{7}-\dfrac{2.1}{3.1}.\)
\(=\dfrac{3}{7}-\dfrac{2}{3}.\)
\(=\dfrac{9}{21}-\dfrac{14}{21}.\)
\(=\dfrac{9-14}{21}=\dfrac{-5}{21}.\)
CHÚC BN HỌC TỐT!!! ^ - ^
