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\(a,4\frac{5}{9}:\frac{\left(-5\right)}{7}+\frac{4}{9}:\frac{-5}{7}\)
\(=\frac{41}{9}.\frac{-7}{5}+\frac{4}{9}.\frac{-7}{5}\)
\(=\frac{-7}{5}.\left(\frac{41}{9}+\frac{4}{9}\right)\)
\(=-\frac{7}{9}.5\)
\(=-7\)
a)Bn Kaito Kid làm rùi!
B)Không viết lại đề
\(=\frac{11}{7}\cdot\left(-\frac{3}{5}+\frac{4}{9}-\frac{2}{5}+\frac{5}{9}\right)=\frac{11}{7}\cdot0=0\)
c)Không viết lại đề
\(A=\left(2+4+...+100\right)\left(\frac{3}{5}\cdot\frac{10}{7}-\frac{6}{7}\right):\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{100}\right)\)
\(=\left(2+4+6+...+100\right)\cdot0\cdot\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{100}\right)=0\)
\(=\frac{7}{6}\cdot\left(\frac{3}{26}-\frac{3}{13}+\frac{1}{10}-\frac{8}{5}\right)=\frac{7}{6}\left(\frac{-3}{26}+\frac{-17}{10}\right)=\frac{7}{6}\cdot\frac{236}{130}=\frac{413}{195}\)
D)
a) \(\frac{-77}{143}+\frac{65}{143}-\frac{66}{143}+\frac{7}{22}\)
= \(\frac{-78}{143}+\frac{7}{22}\)= \(\frac{-6}{11}+\frac{7}{22}\)= \(\frac{-12}{22}+\frac{7}{22}\)
= \(\frac{-5}{22}\)
b) \(\frac{-4}{5}-\frac{20}{170}+\frac{51}{170}+\frac{150}{170}\)= \(\frac{-4}{5}-\frac{221}{170}\)
\(\frac{-4}{5}-\frac{13}{10}\)= \(\frac{-8}{10}-\frac{13}{10}\)=\(\frac{-21}{10}\)
\(=\frac{11}{-5}\cdot\frac{-9}{11}\cdot\frac{15}{-14}\cdot\frac{2}{5}+-\frac{2}{77}\cdot\frac{5}{-3}\)
\(=\frac{9}{5}\cdot-\frac{15}{14}\cdot\frac{2}{5}+\frac{10}{231}\)
\(=-\frac{841}{1155}\)
Ta có : \(\frac{x}{2}=\frac{y}{3};\frac{y}{4}=\frac{y}{5}\)
Quy đòng : \(\frac{x}{8}=\frac{y}{12}=\frac{z}{15}\)
Áp dụng tính chất của dãy tỉ số bằng nhau , ta có :
\(\frac{x}{8}=\frac{y}{12}=\frac{z}{15}=\frac{x+y+z}{8+12+15}=\frac{35}{35}=1\)
\(\Leftrightarrow\begin{cases}\frac{x}{8}=1\Rightarrow x=1.8=8\\\frac{y}{12}=1\Rightarrow y=1.12=12\\\frac{z}{15}=1\Rightarrow z=1.15=15\end{cases}\)
Vậy x = 8 ; y = 12 ; z = 15
-4/5 + 1/-5 = -1 => -4/5 + 1/-5 = -1
-13/22 + -7/22 = -10/11 => -13/22 + -7/22 < -8/11 (vì -10 < -8)
2/3 + -1/5 = 7/15 ; 3/5 = 9/15 => 3/5 > 2/3 + -1/5 (vì 9 >7)
\(\frac{7}{22}:\frac{3}{11}+\frac{7}{22}:\frac{4}{11}\)
\(=\frac{7}{22}:\left(\frac{3}{11}+\frac{4}{11}\right)\)
\(=\frac{7}{22}:\frac{7}{11}\)
\(=\frac{1}{2}\)
ti ck nha
\(\frac{7}{22}\) : (\(\frac{3}{11}\) + \(\frac{4}{11}\) )
\(\frac{7}{22}\) : \(\frac{7}{11}\) =\(\frac{7}{22}\) x \(\frac{11}{7}\) = 2