Ta có:

\(A=\frac{2-\frac{2}{19}+\frac{2}{43}-\frac{2}{1943}}{3-\frac{3}{19}+\frac{3}{43}-\frac{3}{1943}}\)

\(A=\frac{2\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1943}\right)}{3\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1943}\right)}\)

\(A=\frac{2}{3}\)

A =\(\frac{2\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1943}\right)}{3\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1943}\right)}:\frac{4\left(1-\frac{1}{29}+\frac{1}{41}-\frac{1}{2941}\right)}{5\left(1-\frac{1}{29}+\frac{1}{41}-\frac{1}{2941}\right)}\)

=\(\frac{2}{3}:\frac{4}{5}=\frac{2}{3}.\frac{5}{4}=\frac{10}{12}=\frac{5}{6}\)

\(A=\frac{2.\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1943}\right)}{3.\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1943}\right)}:\frac{4\left(1-\frac{1}{29}+\frac{1}{41}-\frac{1}{2941}\right)}{5.\left(1-\frac{1}{29}+\frac{1}{41}-\frac{1}{2941}\right)}=\frac{2}{3}:\frac{4}{5}=\frac{2}{3}.\frac{5}{4}=\frac{5}{6}\)

Xin lỗi nha, mình chỉ biết làm bài này nhõn bằng cách qui đồng nhưng số lớn lắm!

Giúp Mik ik mai nộp oy

Help me :((

\(B=1\frac{6}{41}\cdot\left(\frac{12+\frac{12}{19}-\frac{12}{37}-\frac{12}{53}}{3+\frac{3}{19}-\frac{3}{37}-\frac{3}{53}}\div\frac{4+\frac{4}{15}+\frac{4}{4}+\frac{4}{2013}}{5+\frac{5}{15}+\frac{5}{4}+\frac{5}{2013}}\right)\cdot\frac{124242423}{237373735}\)

\(B=\frac{47}{41}\cdot\left[\frac{12\left(1+\frac{1}{19}-\frac{1}{37}-\frac{1}{53}\right)}{3\left(1+\frac{1}{19}-\frac{1}{37}-\frac{1}{53}\right)}\div\frac{4\left(1+\frac{1}{15}+\frac{1}{4}+\frac{1}{2013}\right)}{5\left(1+\frac{1}{15}+\frac{1}{4}+\frac{1}{2013}\right)}\right]\cdot\frac{123}{235}\)

\(B=\frac{47}{41}\cdot\left[\frac{12}{3}\div\frac{4}{5}\right]\cdot\frac{123}{235}\)

\(B=\frac{3}{5}\cdot3\cdot\frac{5}{4}\)

\(B=\frac{9}{4}\)

Thanks nha Umi

dấu . là gì vậy bạn

dấu nhân

\(\left(-1\frac{1}{6}\right)\left(\frac{1-\frac{3}{5}+\frac{3}{11}-\frac{3}{13}}{\frac{1}{3}-\frac{1}{5}+\frac{1}{11}-\frac{1}{13}}\right)\left(\frac{4-\frac{4}{17}+\frac{4}{19}-\frac{4}{2013}}{5-\frac{5}{7}+\frac{5}{19}-\frac{5}{2013}}\right)\)

\(=-\frac{7}{6}.\left(\frac{3\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{11}-\frac{1}{13}\right)}{\frac{1}{3}-\frac{1}{5}+\frac{1}{11}-\frac{1}{13}}\right):\left(\frac{4.\left(1-\frac{1}{7}+\frac{1}{19}-\frac{1}{2013}\right)}{5.\left(1-\frac{1}{7}+\frac{1}{19}-\frac{1}{2013}\right)}\right)\)

\(=-\frac{7}{6}.3:\frac{4}{5}=-\frac{7}{2}.\frac{5}{4}=-\frac{35}{8}\)

\(A=\frac{2-\frac{2}{19}+\frac{2}{43}-\frac{2}{1995}}{3-\frac{3}{19}+\frac{3}{43}-\frac{3}{1995}}:\frac{4-\frac{4}{29}+\frac{4}{41}-\frac{4}{2941}}{5-\frac{5}{29}+\frac{5}{41}-\frac{5}{2941}}\)

\(\Rightarrow A=\frac{2\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1995}\right)}{3\left(1-\frac{1}{19}+\frac{1}{43}-\frac{1}{1995}\right)}:\frac{4\left(1-\frac{1}{29}+\frac{1}{41}-\frac{1}{2941}\right)}{5\left(1-\frac{1}{29}+\frac{1}{41}-\frac{1}{2941}\right)}\)

\(\Rightarrow A=\frac{2}{3}:\frac{4}{5}\)

\(\Rightarrow A=\frac{2}{3}.\frac{5}{4}\)

\(\Rightarrow A=\frac{10}{12}=\frac{5}{6}\)

thanks bạn

5/6 day