K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Các câu hỏi dưới đây có thể giống với câu hỏi trên
30 tháng 8 2017
a) \(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\)
<=> \(x\left(\dfrac{3}{7}-\dfrac{2}{3}\right)=\dfrac{10}{21}\)
<=> \(x.\left(-\dfrac{5}{21}\right)=\dfrac{10}{21}\)
<=> \(x=-2\)
b) \(\dfrac{7}{35}:\left(x-\dfrac{1}{3}\right)=-\dfrac{2}{25}\)
<=> \(x-\dfrac{1}{3}=-\dfrac{5}{2}\)
<=> \(x=-\dfrac{13}{6}\)
30 tháng 8 2017
a, \(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\)
\(\Leftrightarrow x\left(\dfrac{3}{7}-\dfrac{2}{3}\right)=\dfrac{10}{21}\)
\(\Leftrightarrow x.\dfrac{-5}{21}=\dfrac{10}{21}\)
\(\Leftrightarrow x=-2\)
Vậy ...
b, \(\dfrac{7}{35}:\left(x-\dfrac{1}{3}\right)=\dfrac{-2}{25}\)
\(\Leftrightarrow x-\dfrac{1}{3}=\dfrac{-5}{2}\)
\(\Leftrightarrow x=\dfrac{-13}{6}\)
Vậy ...
NL
2
28 tháng 8 2017
\(\dfrac{3}{7}x-\dfrac{2}{3}x=\dfrac{10}{21}\)
\(x\left(\dfrac{3}{7}-\dfrac{2}{3}\right)=\dfrac{10}{21}\)
\(-\dfrac{5}{21}x=\dfrac{10}{21}\)
\(x=\dfrac{10}{21}:\left(-\dfrac{5}{21}\right)\)
\(x=-2\)
5 tháng 7 2017
chắc h có mấy thành cay r nên ko làm bn lên mạng tải phẩn mêm có cánh iair đó :D
AN
16 tháng 11 2018
1)
a.\(\dfrac{1}{5}+x=\dfrac{13}{50}\)
\(\Leftrightarrow x=\dfrac{13}{50}-\dfrac{1}{5}=\dfrac{13-10}{50}=\dfrac{3}{50}\)
b.\(\dfrac{1}{6}-x=\dfrac{5}{12}\)
\(\Leftrightarrow x=\dfrac{1}{6}-\dfrac{5}{12}=\dfrac{2-5}{12}=-\dfrac{3}{12}=-\dfrac{1}{4}\)
c.\(x\left(-\dfrac{1}{2}\right)^2=\dfrac{1}{16}\)
\(\Leftrightarrow x\left(-\dfrac{1}{2}\right)^2=\dfrac{1}{4}.\left(-\dfrac{1}{2}\right)^2\)
\(\Leftrightarrow x=\dfrac{1}{4}\)
d.\(x:\dfrac{7}{11}=\dfrac{9}{33}\)
\(\Leftrightarrow x=\dfrac{9}{33}.\dfrac{7}{11}=\dfrac{3}{11}.\dfrac{7}{11}=\dfrac{21}{121}\)
e.\(\dfrac{3}{5}.x=-\dfrac{21}{10}\)
\(\Leftrightarrow x=-\dfrac{21}{10}:\dfrac{3}{5}=-\dfrac{21}{10}.\dfrac{5}{3}=-\dfrac{7}{2}\)
30 tháng 11 2022
a: \(\Leftrightarrow\dfrac{5}{3}+\dfrac{4}{3}< x< 3+\dfrac{1}{5}+1+\dfrac{4}{5}\)
=>3<x<5
=>x=4
b: \(\Leftrightarrow\dfrac{1}{3}:2x=-5+\dfrac{1}{4}=-\dfrac{19}{4}\)
=>\(2x=\dfrac{1}{3}:\dfrac{-19}{4}=\dfrac{1}{3}\cdot\dfrac{-4}{19}=\dfrac{-4}{57}\)
=>x=-2/57
c: \(\Leftrightarrow x\cdot\dfrac{-3}{2}=\dfrac{10}{3}-\dfrac{6}{7}=\dfrac{70-18}{21}=\dfrac{52}{21}\)
=>\(x=\dfrac{-52}{21}:\dfrac{3}{2}=\dfrac{-52}{21}\cdot\dfrac{2}{3}=\dfrac{-104}{63}\)
d: \(\Leftrightarrow70+18< x< 120+70\)
=>88<x<190
hay \(x\in\left\{89;90;...;188;189\right\}\)
11 tháng 11 2018
1. Tìm x thuộc N:
\(\left(x-3\right)^6=\left(x-3\right)^7\)
\(\Leftrightarrow\left(x-3\right)^6-\left(x-3\right)^7=0\)
\(\Leftrightarrow\left(x-3\right)^6.\text{[}1-\left(x-3\right)\text{]}=0\)
\(\Leftrightarrow\left(x-3\right)^6.\left(4-x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\4-x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)(thỏa mãn \(x\in N\))
11 tháng 11 2018
2.
Ta có: 6x=4y=3z
\(\Rightarrow\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{4}=\dfrac{2x}{4}=\dfrac{3y}{9}=\dfrac{5z}{20}\)
\(=\dfrac{2x+3y-5z}{4+9-20}=\dfrac{-21}{-7}=3\)
\(\Rightarrow\left\{{}\begin{matrix}x=3.2=6\\y=3.3=9\\z=3.4=12\end{matrix}\right.\)
LH
22 tháng 9 2017
Câu 1 :
\(\dfrac{5}{7}\)+ \(\dfrac{2}{3}\). x =\(\dfrac{3}{10}\)
=> \(\dfrac{2}{3}\).x = \(\dfrac{3}{10}\) - \(\dfrac{5}{7}\)
=> \(\dfrac{2}{3}\). x = \(\dfrac{-29}{70}\)
=> x = \(\dfrac{-29}{70}\): \(\dfrac{2}{3}\)
=> x = \(\dfrac{-87}{140}\)
MH
22 tháng 9 2017
1. \(\dfrac{5}{7}+\dfrac{2}{3}.x=\dfrac{3}{10}\)
<=>\(\dfrac{2}{3}.x=\dfrac{3}{10}-\dfrac{5}{7}=-\dfrac{29}{70}\)
<=>\(x=-\dfrac{29}{70}:\dfrac{2}{3}=-\dfrac{87}{140}\)
Vậy x=\(-\dfrac{87}{140}\)
2.\(\left(x-\dfrac{1}{2}\right):\dfrac{1}{3}+\dfrac{5}{7}=9\dfrac{5}{7}\)
\(< =>\left(x-\dfrac{1}{2}\right):\dfrac{1}{3}=9\dfrac{5}{7}-\dfrac{5}{7}=9\)
\(< =>x-\dfrac{1}{2}=9.\dfrac{1}{3}=3\\ < =>x=\dfrac{1}{2}+3=\dfrac{7}{2}\)
Vậy x=\(\dfrac{7}{2}\)
9 tháng 7 2017
a, \((\dfrac{1}{3}-2x)^2+\dfrac{5}{4}=\dfrac{21}{16}\)
\((\dfrac{1}{3})^2\) - (2x)2 = \(\dfrac{1}{16}\)
=> \(\dfrac{1}{9}\)- (2x)2=\(\dfrac{1}{16}\)
=> (2x)2=\(\dfrac{7}{144}\)
=> 22.x2=\(\dfrac{7}{144}\)
=> 4.x2 =\(\dfrac{7}{144}\)
=> x2= \(\dfrac{7}{576}\)
=>x= +\(\sqrt{\dfrac{7}{576}}\) hoặc - \(\sqrt{\dfrac{7}{576}}\)
b,\(\dfrac{4-x}{3}=\dfrac{5}{2}\)
=> (4-x).2 = 5.3
=>8-x.2 = 15
=> x.2 = 8-15
=>x.2 = -7
=> x= -\(\dfrac{7}{2}\)
c. 7\(\dfrac{1}{3}\)- | x-1| : 2= \(\dfrac{5}{2}\)
=>\(\dfrac{22}{3}\)-|x-1| .\(\dfrac{1}{2}\) =\(\dfrac{5}{2}\)
=> |x-1|.\(\dfrac{1}{2}\)=\(\dfrac{29}{6}\)
=> |x-1| =\(\dfrac{29}{3}\)
+) x-1 = \(\dfrac{29}{3}\)=> x=\(\dfrac{32}{3}\)
+) x-1 = -\(\dfrac{29}{3}\)=> x=-\(\dfrac{26}{3}\)
Vậy x= \(\dfrac{32}{3}\)hoặc x=-\(\dfrac{26}{3}\)
`3/7 x -2/3 x =10/21`
`=> (3/7-2/3)x=10/21`
`=> ( 9/21 - 14/21)x=10/21`
`=>-5/21 x=10/21`
`=> x=10/21 : (-5/21)`
`=> x=10/21 xx (-21/5)`
`=>x=-2`
(3/7 - 2/3).x = 10/21
-5/21.x = 10/21
x = 10/21 : (-5/21)
x = -2
vậy x = -2