![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a.x+\frac{7}{12}=\frac{17}{18}-\frac{1}{9}\) b) \(\frac{29}{30}-\left(\frac{13}{23}+x\right)=\frac{7}{69}\)
\(x+\frac{7}{12}=\frac{5}{6}\) \(\left(\frac{13}{23}+x\right)=\frac{29}{30}-\frac{7}{69}\)
\(x=\frac{5}{6}-\frac{7}{12}\) \(\left(\frac{13}{23}+x\right)=\frac{199}{230}\)
\(x=\frac{1}{4}\) \(x=\frac{199}{230}-\frac{13}{23}\)
VẬY \(x=\frac{1}{4}\) \(x=\frac{3}{10}\)
VẬY..............
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
1: x-1/2=3/8
=>x=3/8+1/2
=>x=3/8+4/8=7/8
2: x+1/5=3-3/2
=>x+1/5=3/2
=>x=3/2-1/5=15/10-2/10=13/10
3: =>x*1/12=2/3-1/4=8/12-3/12=5/12
=>x=5
4: =>2x-9=21
=>2x=30
=>x=15
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: -7/15=-28/60
5/12=25/60
b: 1/5=6/30
-2/3=-20/30
7/10=21/30
\(-\dfrac{7}{15}=\dfrac{-7.4}{15.4}=\dfrac{-28}{60};\dfrac{5}{12}=\dfrac{5.5}{12.5}=\dfrac{25}{60}\)
\(\dfrac{1}{5}=\dfrac{1.6}{5.6}=\dfrac{6}{30};\dfrac{-2}{3}=\dfrac{-2.10}{3.10}=\dfrac{-20}{30};\dfrac{7}{10}=\dfrac{7.3}{10.3}=\dfrac{21}{30}\)
\(a,S=1-5+5^2-5^3+...+5^{98}-5^{99}\\ 5S=5-5^2+5^3-5^4+...+5^{99}-5^{100}\\ 5S+S=1-5^{100}\\ S=\dfrac{1-5^{100}}{6}\)
\(Do\) \(S\in Z\Rightarrow1-5^{100}⋮6\Rightarrow5^{100}\) chia 6 dư 1