Sửa đề : \(-\dfrac{19}{37}=\dfrac{19}{37}\)

\(\dfrac{19}{37}-\dfrac{31}{24}-\dfrac{19}{37}+1\dfrac{7}{24}-\dfrac{2}{13}\)

\(=\dfrac{19}{37}-\dfrac{31}{24}+\dfrac{19}{37}+\dfrac{31}{24}-\dfrac{2}{13}\)

\(=\left(\dfrac{19}{37}-\dfrac{19}{37}\right)+\left(-\dfrac{31}{24}+\dfrac{31}{24}\right)-\dfrac{2}{13}=-\dfrac{2}{13}\)

Sửa đề: \(\dfrac{19}{37}-\dfrac{31}{24}+\dfrac{-19}{37}+1\dfrac{7}{24}-\dfrac{2}{13}\)

Ta có: \(\dfrac{19}{37}-\dfrac{31}{24}+\dfrac{-19}{37}+1\dfrac{7}{24}-\dfrac{2}{13}\)

\(=\left(\dfrac{19}{37}+\dfrac{-19}{37}\right)+\left(\dfrac{-31}{24}+1+\dfrac{7}{24}\right)-\dfrac{2}{13}\)

\(=\dfrac{-2}{13}\)

\(\dfrac{19}{37}-\dfrac{31}{24}-\dfrac{-19}{37}+1\dfrac{7}{24}-\dfrac{2}{13}=\dfrac{19}{37}-\dfrac{31}{24}+\dfrac{19}{37}+\dfrac{31}{24}-\dfrac{2}{13}=\left(\dfrac{19}{37}+\dfrac{19}{37}\right)+\left(\dfrac{-31}{24}+\dfrac{31}{24}\right)-\dfrac{2}{13}=\dfrac{38}{31}+0-\dfrac{2}{13}=\dfrac{122}{403}\)

=-0,254093

làm rõ ra nha bạn

d: \(-37\cdot\left(-19\right)+37\left(-19\right)\)

\(=-19\left(-37+37\right)\)

\(=-19\cdot0=0\)

e: \(\left(29-9\right)\cdot\left(-9\right)+\left(-13-7\right)\cdot21\)

\(=20\cdot\left(-9\right)+\left(-20\right)\cdot21\)

\(=-20\left(9+21\right)\)

\(=-20\cdot30=-600\)

h: \(12\cdot\left(-47\right)+12\left(-19\right)+\left(-66\right)\cdot88\)

\(=12\left(-47-19\right)+\left(-66\right)\cdot88\)

\(=\left(-66\right)\cdot12+\left(-66\right)\cdot88\)

\(=-66\left(12+88\right)\)

\(=-66\cdot100=-6600\)

Ta có: \(B=\dfrac{11}{13}\cdot\dfrac{40}{13}+\dfrac{37}{5}:\dfrac{7}{33}-\left(\dfrac{11}{13}+\dfrac{33}{7}:\dfrac{5}{2}\right)\)

\(=\dfrac{440}{169}+\dfrac{37}{5}\cdot\dfrac{33}{7}-\dfrac{11}{13}-\dfrac{33}{7}\cdot\dfrac{2}{5}\)

\(=\dfrac{297}{169}+\dfrac{33}{7}\cdot\left(\dfrac{37}{5}-\dfrac{2}{5}\right)\)

\(=\dfrac{297}{169}+\dfrac{33}{7}\cdot7\)

\(=\dfrac{297}{169}+33=\dfrac{5874}{169}\)

Bạn bấn vào đây Giúp tôi giải toán - Hỏi đáp, thảo luận về toán học - Học toán với OnlineMath

\(A=\frac{34}{7.13}+\frac{51}{13.22}+\frac{85}{22.37}+\frac{68}{37.49}\)

\(=\frac{17.2}{7.13}+\frac{17.3}{13.22}+\frac{17.5}{22.37}+\frac{17.4}{37.49}\)

\(=17\left(\frac{2}{7.13}+\frac{3}{13.22}+\frac{5}{22.37}+\frac{4}{37.49}\right)\)

\(=\frac{17}{3}\left(\frac{6}{7.13}+\frac{9}{13.22}+\frac{15}{22.37}+\frac{12}{37.49}\right)\)

\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{13}+\frac{1}{13}-\frac{1}{22}+...+\frac{1}{37}-\frac{1}{49}\right)\)

\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{49}\right)\)\(=\frac{17}{3}.\frac{6}{49}=\frac{17.2}{49}=\frac{34}{49}\)

Có : \(\frac{17}{24}=\frac{34}{48}\)

Vì 48 < 49 => \(\frac{34}{48}>\frac{34}{49}\). Hay \(\frac{17}{24}>A\)

cảm ơn Văn B ? nha !