\(\Rightarrow A=\frac{\frac{1}{2}-\frac{1}{5}+\frac{1}{7}}{\frac{3}{8}-\frac{3}{5}+\frac{3}{7}}+\frac{\frac{1}{2}+\frac{1}{3}-\frac{1}{5}}{\frac{3}{4}+\frac{1}{2}+\frac{3}{10}}\)

\(\Rightarrow A=\frac{\frac{1}{2}-\frac{1}{5}+\frac{1}{7}}{3.\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{7}\right)}+\frac{\frac{1}{2}+\frac{1}{3}-\frac{1}{5}}{\frac{3}{2}.\left(\frac{1}{2}+\frac{1}{3}-\frac{1}{5}\right)}\)

\(\Rightarrow A=\frac{1}{3}+\frac{2}{3}\)

\(\Rightarrow A=1\)

(2/5+2/7-2/11):(3/7-3/11+3/5) =2/5+2/7-2/11.7/3-11/3+5/3=2/1+2/1-2/1.1/3-1/3+1/3=2+1/3=7/3                                                                          Em đây mới học lớp 6 nên hay xem kĩ lại và tính bang máy tính  

a, 2/3

b,1

nhớ nhé

\(\frac{\frac{1}{8}-\frac{1}{5}+\frac{1}{7}}{\frac{3}{8}-\frac{3}{5}+\frac{3}{7}}+\frac{\frac{1}{2}+\frac{1}{3}-\frac{1}{5}}{\frac{3}{4}+\frac{1}{2}-\frac{3}{10}}\)\(=\frac{\frac{1}{8}-\frac{1}{5}+\frac{1}{7}}{3\left(\frac{1}{8}-\frac{1}{5}+\frac{1}{7}\right)}+\frac{60.\left(\frac{1}{2}+\frac{1}{3}-\frac{1}{5}\right)}{60.\left(\frac{3}{4}+\frac{1}{2}-\frac{3}{10}\right)}\)

\(=\frac{1}{3}+\frac{30+20-12}{45+30-18}\)\(=\frac{1}{3}+\frac{38}{57}=1\)

\(\frac{1\left(0,125-\frac{1}{5} +\frac{1}{7}\right)}{3\left(0,125-\frac{1}{5}+\frac{1}{7}\right)}+\frac{1\left(\frac{1}{2}+\frac{1}{3}-0,2\right)}{\frac{3}{2}\left(\frac{1}{2}+\frac{1}{3}-0,2\right)}\)\(=\frac{1}{3}+\frac{1}{\frac{3}{2}}=\frac{1}{3}+\frac{2}{3}=\frac{3}{3}=1\)

Vậy giá trị biểu thức trên bằng 1

\(\frac{0,125-\frac{1}{5}+\frac{1}{7}}{0,375-\frac{3}{5}+\frac{3}{7}}+\frac{\frac{1}{2}+\frac{1}{3}-0,2}{\frac{3}{4}+0,5-\frac{3}{10}}\)

\(=\frac{\frac{19}{280}}{\frac{57}{280}}+\frac{\frac{19}{30}}{\frac{19}{20}}\)

\(=\frac{1}{3}+\frac{2}{3}\)

\(=1.\)

Chúc bạn học tốt!

\(A=\frac{1.\left(0,125-\frac{1}{5}+\frac{1}{7}\right)}{3.\left(0,125-\frac{1}{5}+\frac{1}{7}\right)}+\frac{-\frac{247}{6}}{0,95}\)

\(=\frac{1}{3}+\frac{-130}{3}\)

\(=\frac{1-130}{3}=-\frac{129}{3}=-43\)

(lớp 6 HKI chưa học số nguyên âm!)

a: \(\dfrac{1+\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}}{1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}}:\dfrac{13+\dfrac{13}{2}+\dfrac{13}{3}+\dfrac{13}{4}}{17-\dfrac{17}{2}+\dfrac{17}{3}-\dfrac{17}{4}}\)

\(=\dfrac{1+\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}}{1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}}\cdot\dfrac{17\left(1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}\right)}{13\left(1+\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}\right)}=\dfrac{17}{13}\)

b: \(\dfrac{0.125-\dfrac{1}{5}+\dfrac{1}{7}}{0.375-\dfrac{3}{5}+\dfrac{3}{7}}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-0.2}{\dfrac{3}{4}+0.5-\dfrac{3}{10}}\)

\(=\dfrac{\dfrac{1}{8}-\dfrac{1}{5}+\dfrac{1}{7}}{\dfrac{3}{8}-\dfrac{3}{5}+\dfrac{3}{7}}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{5}}{\dfrac{3}{4}+\dfrac{3}{6}-\dfrac{3}{10}}\)

\(=\dfrac{1}{3}+\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{5}}{\dfrac{3}{2}\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{5}\right)}=\dfrac{1}{3}+\dfrac{2}{3}=1\)

92/57