Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) A = 3/7
b) B = 73/13
c) C = 37/7
d) D = 12
ba câu a) ,b) ,c) bn đổi ra hỗn số giúp mk nha
tick cho tớ nha
Bài 2:
a: Để A là phân số thì x+6<>0
hay x<>-6
b: Để A là sốnguyen thì \(x+6-13⋮x+6\)
\(\Leftrightarrow x+6\in\left\{1;-1;13;-13\right\}\)
hay \(x\in\left\{-5;-7;7;-19\right\}\)
a: \(=\dfrac{4\cdot2+4\cdot9}{55}+\dfrac{5}{6}=\dfrac{4}{5}+\dfrac{5}{6}=\dfrac{49}{30}\)
b: \(=\dfrac{3}{2}\cdot\dfrac{3}{5}-\left(\dfrac{3}{7}+\dfrac{3}{20}\right)\cdot\dfrac{10}{3}\)
\(=\dfrac{9}{10}-\dfrac{81}{140}\cdot\dfrac{10}{3}\)
\(=\dfrac{9}{10}-\dfrac{27}{14}=\dfrac{-36}{35}\)
c: \(=15+\dfrac{3}{13}-3-\dfrac{4}{7}-8-\dfrac{3}{13}\)
\(=4-\dfrac{4}{7}=\dfrac{24}{7}\)
d: \(=\dfrac{-7}{9}\left(\dfrac{4}{11}+\dfrac{7}{11}\right)+5+\dfrac{7}{9}=5\)
\(a)\left(6\dfrac{4}{9}+3\dfrac{7}{11}\right)-4\dfrac{4}{9}\)
\(=\left(\dfrac{58}{9}+\dfrac{40}{11}\right)-\dfrac{40}{9}\)
\(=\dfrac{58}{9}+\dfrac{40}{11}-\dfrac{40}{9}\)
\(=\left(\dfrac{58}{9}+\dfrac{40}{9}\right)+\dfrac{40}{11}\)
\(=2+\dfrac{40}{11}\)
\(=\dfrac{62}{11}\)
\(b)\left(11\dfrac{2}{7}+3\dfrac{2}{5}\right)-7\dfrac{2}{7}\)
\(=\left(\dfrac{79}{7}+\dfrac{17}{5}\right)-\dfrac{51}{7}\)
\(=\left(\dfrac{79}{7}-\dfrac{51}{7}\right)+\dfrac{17}{5}\)
\(=4+\dfrac{17}{5}\)
\(=\dfrac{37}{5}\)
a: \(=\dfrac{-28}{36}+\dfrac{15}{36}-\dfrac{26}{36}=\dfrac{-39}{36}=\dfrac{-13}{12}\)
b: \(=\dfrac{11}{9}\left(\dfrac{15}{4}-\dfrac{7}{4}-\dfrac{5}{4}\right)=\dfrac{11}{9}\cdot\dfrac{3}{4}=\dfrac{11}{12}\)
c: \(=15+\dfrac{9}{7}+6+\dfrac{2}{3}-5-\dfrac{5}{9}\)
\(=16+\dfrac{88}{63}=\dfrac{1096}{63}\)
d: \(=\dfrac{5}{6}-\dfrac{1}{3}+\dfrac{2}{18}\)
\(=\dfrac{15-6+2}{18}=\dfrac{11}{18}\)
a: \(\Leftrightarrow\dfrac{a}{10}=\dfrac{7}{b}=\dfrac{c}{20}=\dfrac{1}{2}\)
=>a=5; b=14; c=10
b: \(\Leftrightarrow\dfrac{a}{9}=\dfrac{-8}{b}=\dfrac{c}{-21}=\dfrac{-2}{3}\)
=>a=-6; b=12; c=14
Giải:
Ta có: \(\dfrac{6}{7}a=\dfrac{9}{11}b=\dfrac{2}{3}c\Rightarrow\dfrac{a}{\dfrac{7}{6}}=\dfrac{b}{\dfrac{11}{9}}=\dfrac{c}{\dfrac{3}{2}}\)
Đặt \(\dfrac{a}{\dfrac{7}{6}}=\dfrac{b}{\dfrac{11}{9}}=\dfrac{c}{\dfrac{3}{2}}=k\Rightarrow\left\{{}\begin{matrix}a=\dfrac{7}{6}k\\b=\dfrac{11}{9}k\\c=\dfrac{3}{2}k\end{matrix}\right.\)
Mà \(a+b+c=210\)
\(\Rightarrow\dfrac{7}{6}k+\dfrac{11}{9}k+\dfrac{3}{2}k=210\)
\(\Rightarrow\dfrac{35}{9}k=210\)
\(\Rightarrow k=54\)
\(\Rightarrow\left\{{}\begin{matrix}a=63\\b=66\\c=81\end{matrix}\right.\)
Vậy \(a=63;b=66;c=81\)
mình mới lớp 6 nên không dùng dãy tỉ số bằng nhau đc bạn ơi