Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 1 : Ta có:
\(\frac{7+\frac{7}{11}+\frac{7}{23}+\frac{7}{31}}{9+\frac{9}{11}+\frac{9}{23}+\frac{9}{31}}\)
= \(\frac{7.\left(1+\frac{1}{11}+\frac{1}{23}+\frac{1}{31}\right)}{9.\left(1+\frac{1}{11}+\frac{1}{23}+\frac{1}{31}\right)}\)
= \(\frac{7}{9}\)
Bài 2 :
\(\frac{x}{2}+\frac{3x}{4}+\frac{5x}{6}=\frac{10}{24}\)
=> \(\frac{12x+18x+20x}{24}=\frac{10}{24}\)
=> 50x = 10
=> x = 10 : 50
=> x = 1/5
Bài 3 : Để A nhận giá trị nguyên thì 3 \(⋮\)x + 3
<=> x + 3 \(\in\)Ư(3) = {1; -1; 3; -3}
Lập bảng :
x + 3 | 1 | -1 | 3 | -3 |
x | -2 | -4 | 0 | -6 |
Vậy
=>(x+9/11)=0 hoặc (x-25/31)=0
+/Nếu x+9/11=0
=>x=-9/11
+/Nếu x-25/31=0
=>x=25/31
a) \(x=\frac{7}{25}+\frac{-1}{5}=\frac{7}{25}+\frac{-5}{25}=\frac{2}{25}\)
b) \(x=\frac{5}{11}+\frac{4}{-9}=\frac{45}{99}+\frac{-44}{99}=\frac{1}{99}\)
c) \(\frac{5}{9}+\frac{x}{-1}=\frac{-1}{3}\)
\(\Rightarrow\frac{x}{-1}=\frac{-1}{3}-\frac{5}{9}\)
\(\Rightarrow\frac{x}{-1}=\frac{-8}{9}\)
\(\Rightarrow x=\frac{\left(-8\right).\left(-1\right)}{9}=\frac{8}{9}\)
a/\(\frac{13}{11}.\frac{22}{26}-x^2=\frac{7}{16}\)
\(\Rightarrow1-x^2=\frac{7}{16}\)
\(\Rightarrow x^2=\frac{9}{16}\)
\(\Rightarrow x=\orbr{\begin{cases}\frac{3}{4}\\-\frac{3}{4}\end{cases}}\)
\(a,\frac{13}{11}.\frac{22}{26}-x^2=\frac{7}{16}\)
\(1-x^2=\frac{7}{16}\)
\(x^2=1-\frac{7}{16}=\frac{9}{16}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{3}{4}\\x=-\frac{3}{4}\end{cases}}\)
\(b,x^2+-\frac{9}{25}=\frac{2}{5}.\frac{8}{5}\)
\(x^2+-\frac{9}{25}=\frac{16}{25}\)
\(x^2=\frac{16}{25}--\frac{9}{25}=1\)
\(\Rightarrow\orbr{\begin{cases}x=1\\x=-1\end{cases}}\)
học tốt ~~~
\(\frac{25-x}{995}+\frac{21-x}{997}+\frac{17-x}{999}=\frac{11-x}{334}\)
\(\Rightarrow\frac{25-x}{995}+2+\frac{21-x}{997}+\frac{17-x}{999}+2=\frac{11-x}{334}+6\)
\(\Rightarrow\frac{25-x}{995}+\frac{1990}{995}+\frac{21-x}{997}+\frac{1994}{997}+\frac{17-x}{999}+\frac{1998}{999}=\frac{11-x}{334}+\frac{2004}{334}\)
\(\Rightarrow\frac{2015-x}{995}+\frac{2015-x}{997}+\frac{2015-x}{999}=\frac{2015-x}{334}\)
\(\Rightarrow\frac{2015-x}{995}+\frac{2015-x}{997}+\frac{2015-x}{999}-\frac{2015-x}{334}=0\)
\(\Rightarrow\left(2015-x\right)\left(\frac{1}{995}+\frac{1}{997}+\frac{1}{999}+\frac{1}{334}\right)=0\)
\(\Rightarrow2015-x=0\left(\text{vì }\frac{1}{995}+\frac{1}{997}+\frac{1}{999}+\frac{1}{334}\ne0\right)\)
\(\Rightarrow x=2015\)
\(a)\frac{1}{3}+\frac{-2}{5}+\frac{1}{6}+\frac{-1}{5}\le x< \frac{-3}{4}+\frac{2}{7}+\frac{-1}{4}+\frac{3}{5}+\frac{5}{7}\)
\(\Rightarrow\frac{1}{3}+\frac{1}{6}+\frac{-2}{5}+\frac{-1}{5}\le x< \frac{-3}{4}+\frac{-1}{4}+\frac{2}{7}+\frac{5}{7}+\frac{3}{5}\)
\(\Rightarrow\frac{2}{6}+\frac{1}{6}+\frac{-3}{5}\le x< -1+1+\frac{3}{5}\)
\(\Rightarrow\frac{1}{2}+\frac{-3}{5}\le x< \frac{3}{5}\)
\(\Rightarrow\frac{-1}{10}\le x< \frac{6}{10}\)
\(\Rightarrow-1\le x< 6\)
\(\Rightarrow x\in\left\{-1;0;1;2;3;4;5\right\}\)
Bài b tương tự
\(X-\left(\frac{31}{5}+\frac{31}{15}+\frac{31}{35}+\frac{31}{63}+\frac{31}{99}+\frac{31}{143}\right)=\frac{9}{13}\)
\(X-\left(\frac{31}{5}+\frac{31}{3\cdot5}+\frac{31}{5\cdot7}+\frac{31}{7\cdot9}+\frac{31}{9\cdot11}+\frac{31}{11\cdot13}\right)=\frac{9}{13}\)
\(X-\left[\frac{31}{2}\cdot\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+\frac{1}{11}-\frac{1}{13}\right)+\frac{31}{5}\right]=\frac{9}{13}\)
\(X-\left[\frac{31}{2}\cdot\left(\frac{1}{3}-\frac{1}{13}\right)+\frac{31}{5}\right]=\frac{9}{13}\)
\(X-\left[\frac{31}{2}\cdot\frac{10}{39}+\frac{31}{5}\right]=\frac{9}{13}\)
\(X-\frac{1984}{195}=\frac{9}{13}\)
\(\Rightarrow X=\frac{9}{13}+\frac{1984}{195}=\frac{163}{15}\)
Bạn ơi câu trả lời này chưa rõ ràng ( tìm x mà không có kết quả thì ko tìm được )
kết quả bằng 0