Câu 1: Tìm x biết: 4 X 35% : x = 14% A.x=15 B.x=12 C.x=10 D.x=20
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)
a.\(3+x=-8\)
\(x=-8-3\)
\(x=-11\)
b.\(\left(35+x\right)-12=27\)
\(35+x=27+12\)
\(35+x=39\)
\(x=39-35\)
\(x=4\)
c.\(2^x+15=31\)
\(2^x=31-15\)
\(2^x=16\)
\(2^x=2^4\)
\(x=4\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{x}{4}=\frac{y}{3}\)
\(\Rightarrow\frac{x+y}{4+3}=\frac{x}{4}=\frac{y}{3}\) mà x + y = 14
\(\Rightarrow\frac{14}{7}=\frac{x}{4}=\frac{y}{3}\)
\(\Rightarrow2=\frac{x}{4}=\frac{y}{3}\)
\(\Rightarrow\hept{\begin{cases}x=2\cdot4=8\\y=2\cdot3=6\end{cases}}\)
![](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 - 3 4 = 3 5 x = 3 5 + 3 4 x = 27 20
b . x : 1 4 = 16 x = 16 x 1 4 x = 4
![](https://rs.olm.vn/images/avt/0.png?1311)
Đáp án cần chọn là: D
−x–14+35=−26−(−11)
−x+21=−26+11
21–x=−15
x =21+15
x=36
![](https://rs.olm.vn/images/avt/0.png?1311)
\(35-\left|2x-1\right|=14\)
\(\Leftrightarrow\left|2x-1\right|=21\)
\(\Leftrightarrow\orbr{\begin{cases}2x-1=21\left(x\ge\frac{1}{2}\right)\\2x-1=-21\left(x< \frac{1}{2}\right)\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x=22\\2x=-20\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=11\left(TM\right)\\x=-10\left(TM\right)\end{cases}}\)
\(35-|2x-1|=14\)
\(|2x-1|=21\)
\(\Rightarrow\orbr{\begin{cases}2x-1=21\\2x-1=-21\end{cases}\Rightarrow\orbr{\begin{cases}2x=22\\2x=-20\end{cases}\Rightarrow}\orbr{\begin{cases}x=11\\x=-10\end{cases}}}\)
\(C.x=10\)
đăng kí CTV chưa zậy anh ?