\(\dfrac{23}{19}.\left(\dfrac{17}{29}-\dfrac{19}{23}\right)-\dfrac{17}{29}.\dfrac{4}{19}\)
\(=\dfrac{23}{19}.\dfrac{17}{29}-\dfrac{23}{19}.\dfrac{19}{23}-\dfrac{17}{29}.\dfrac{4}{19}\)
\(=\dfrac{23}{19}.\dfrac{17}{29}-\dfrac{17}{29}.\dfrac{4}{19}-1\)
\(=\dfrac{17}{19.29}.\left(23-4\right)-1\)
\(=\dfrac{17}{19.29}.19-1\)
\(=\dfrac{17}{29}-1\)
\(=-\dfrac{12}{29}\)
Tìm các số nguyên dương x biết:
a)\(\dfrac{19}{-23}\)\(< \dfrac{-19}{x}\)\(< \dfrac{19}{-29}\) b)\(\dfrac{2}{3}\)\(< \dfrac{88}{x}\)\(< \dfrac{11}{16}\) c)\(\dfrac{4}{x}\)\(< \dfrac{x}{8}\)\(< \dfrac{5}{x}\)
f\(\dfrac{-2}{17}+\dfrac{15}{23}+\dfrac{-15}{17}+\dfrac{4}{19}+\dfrac{8}{23}\)
g \(\dfrac{-1}{2}+\dfrac{3}{21}+\dfrac{-2}{6}+\dfrac{-5}{30}\)
So sánh phân số:
a) \(\dfrac{-15}{17}\)và\(\dfrac{-19}{21}\) c) \(\dfrac{-317}{633}\)và \(\dfrac{-371}{743}\)
b)\(\dfrac{-23}{49}\)và \(\dfrac{-25}{47}\) d) \(\dfrac{-24}{35}\) và \(\dfrac{-19}{30}\)
\(\dfrac{2x+19}{21}-\dfrac{2x+17}{23}=\dfrac{2x+7}{33}-\dfrac{2x+5}{35}\) tìm x
\(\dfrac{29}{19}\cdot\dfrac{49}{51}+\dfrac{29}{19}\cdot\dfrac{34}{51}-\dfrac{29}{19}\cdot\dfrac{32}{51}\)
C = \(\dfrac{4}{9}\)\(\times\)\(\dfrac{13}{17}\)+\(\dfrac{4}{17}\)\(\times\)\(\dfrac{4}{9}\)+\(\dfrac{2}{9}\)
D = \(\dfrac{8}{19}\)\(\times\)\(\dfrac{5}{11}\)+\(\dfrac{7}{11}\)\(\times\dfrac{8}{19}+\dfrac{12}{11}\times\dfrac{11}{19}\)
3/ Tính hợp lí :
a/ P = \(\dfrac{-2}{7}\) + \(\dfrac{14}{29}\) + \(\dfrac{12}{33}\) + \(\dfrac{15}{29}\) + \(\dfrac{21}{33}\) + \(\dfrac{2}{7}\)
b/ \(\dfrac{2}{7}\) . \(\dfrac{5}{19}\) + \(\dfrac{2}{7}\) . \(\dfrac{14}{19}\) + \(\dfrac{21}{19}\) - \(\dfrac{2}{7}\) . \(\dfrac{1}{5}\)
bài 1 tính :
\(\dfrac{-8}{9}\) . \(\dfrac{12}{19}\) . \(\dfrac{9}{-4}\) . \(\dfrac{19}{24}\) \(\dfrac{-5}{16}\) . \(\dfrac{17}{15}\) : \(\dfrac{-17}{8}\)
\(\dfrac{4}{13}\) . \(\dfrac{2}{7}\) + \(\dfrac{-3}{26}\) + \(\dfrac{4}{13}\) . \(\dfrac{5}{7}\) \(\dfrac{6}{11}\) . \(\dfrac{3}{4}\) + \(\dfrac{-12}{60}\) +\(\dfrac{-3}{4}\) .\(\dfrac{-5}{11}\)
1)\(\dfrac{1}{2}+\dfrac{13}{19}-\dfrac{4}{9}+\dfrac{6}{19}+\dfrac{5}{18}\)
2)\(\dfrac{ }{\dfrac{-20}{23}+\dfrac{2}{3}-\dfrac{3}{23}+\dfrac{2}{5}+\dfrac{7}{15}}\)
3)\(\dfrac{ }{\dfrac{4}{3}+\dfrac{-11}{31}+\dfrac{3}{10}-\dfrac{20}{31}-\dfrac{2}{5}}\)
4)\(\dfrac{ }{\dfrac{5}{7}.\dfrac{5}{11}+\dfrac{5}{7}.\dfrac{2}{11}-\dfrac{5}{7}.\dfrac{14}{11}}\)
