DT
2
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
21 tháng 6 2017
\(4)\)
\(\dfrac{-\left(-x\right)}{5}-\dfrac{2}{10}=\dfrac{1}{-5}-\dfrac{7}{50}\)
\(\Leftrightarrow\dfrac{x}{5}-\dfrac{2}{10}=\dfrac{1}{-5}-\dfrac{7}{50}\)
\(\dfrac{2x}{10}-\dfrac{2}{10}=\dfrac{-10}{50}-\dfrac{7}{50}\)
\(\Leftrightarrow\dfrac{2x-2}{10}=\dfrac{-10-7}{50}\)
\(\dfrac{2x-2}{10}=\dfrac{-17}{50}\)
\(\Leftrightarrow50\left(2x-2\right)=-17.10\)
\(100x-100=-170\)
\(100x=-170+100=-70\)
\(x=-70:100=\dfrac{-7}{10}\)
\(\dfrac{x+1}{5}=\dfrac{7}{x-1}\)
\(\left(x+1\right)\left(x-1\right)5.7\)
\(x\left(x-1\right)+1\left(x-1\right)=35\)
\(x^2-x+x-1=35\)
\(x^2-1=35\)
\(x^2=36\)
\(\Leftrightarrow x=\left\{\pm6\right\}\)
21 tháng 6 2017
bạn có thể giải đc các bài còn lại k ? K phải mk ép bạn đâu nhưng nếu bạn lm đc thì giúp mk nha
HN
9 tháng 4 2017
a) \(\dfrac{2}{3}x-\dfrac{3}{2}x=\dfrac{5}{12}\)
\(-\dfrac{5}{6}x=\dfrac{5}{12}\)
\(x=-\dfrac{1}{2}\)
b) \(\dfrac{2}{5}+\dfrac{3}{5}\cdot\left(3x-3.7\right)=-\dfrac{53}{10}\)
\(\dfrac{3}{5}\left(3x-3.7\right)=-\dfrac{57}{10}\)
\(3x-3.7=-\dfrac{19}{2}\)
\(3x=-5.8\)
\(x=-\dfrac{29}{15}\)
c) \(\dfrac{7}{9}:\left(2+\dfrac{3}{4}x\right)+\dfrac{5}{9}=\dfrac{23}{27}\)
\(\dfrac{7}{9}:\left(2+\dfrac{3}{4}x\right)=\dfrac{8}{27}\)
\(2+\dfrac{3}{4}x=\dfrac{21}{8}\)
\(\dfrac{3}{4}x=\dfrac{5}{8}\)
\(x=\dfrac{5}{6}\)
d) \(-\dfrac{2}{3}x+\dfrac{1}{5}=\dfrac{3}{10}\)
\(-\dfrac{2}{3}x=\dfrac{1}{10}\)
\(x=-\dfrac{3}{20}\)
7 tháng 4 2017
a) (1/7.x-2/7).(-1/5.x-2/5)=0
=> 1/7.x-2/7=0hoặc-1/5.x-2/5=0
*1/7.x-2/7=0
1/7.x=0+2/7
1/7.x=2/7
x=2/7:1/7
x=2
b)1/6.x+1/10.x-4/5.x+1=0
(1/6+1/10-4/5).x+1=0
(1/6+1/10-4/5).x=0-1
(1/6+1/10-4/5).x=-1
(-8/15).x=-1
x=-1:(-8/15) =15/8
30 tháng 3 2017
\(\dfrac{-2}{3}.x+\dfrac{1}{5}=\dfrac{3}{10}\)
\(\dfrac{-2}{3}.x=\dfrac{3}{10}-\dfrac{1}{5}\)
\(\dfrac{-2}{3}.x=\dfrac{3}{10}-\dfrac{2}{10}\)
\(\dfrac{-2}{3}.x=\dfrac{1}{10}\)
\(x=\dfrac{1}{10}:\dfrac{-2}{3}\)
\(x=\dfrac{1}{10}.\dfrac{-3}{2}\)
\(x=\dfrac{-3}{20}\)
4 tháng 4 2017
\(60\%x=\dfrac{1}{3}.6\dfrac{1}{3}\\ \dfrac{3}{5}x=\dfrac{1}{3}.\dfrac{19}{3}\\ \dfrac{3}{5}x=\dfrac{19}{9}\\ x=\dfrac{19}{9}:\dfrac{3}{5}\\ x=\dfrac{19}{9}.\dfrac{5}{3}\\ x=\dfrac{95}{27}\)
4 tháng 4 2017
\(\dfrac{-2}{3}.x+\dfrac{1}{5}=\dfrac{3}{10}\\ \dfrac{-2}{3}.x=\dfrac{3}{10}-\dfrac{1}{5}\\ \dfrac{-2}{3}.x=\dfrac{3}{10}-\dfrac{2}{10}\\ \dfrac{-2}{3}.x=\dfrac{1}{10}\\ x=\dfrac{1}{10}:\dfrac{-2}{3}\\ x=\dfrac{1}{10}.\dfrac{-3}{2}\\ x=\dfrac{-3}{20}\)
25 tháng 3 2017
1) \(\dfrac{5}{3}-x+\dfrac{1}{5}=\dfrac{-3}{10}\\ x+\dfrac{1}{5}=\dfrac{5}{3}-\left(\dfrac{-3}{10}\right)\\ x+\dfrac{1}{5}=\dfrac{5}{3}+\dfrac{3}{10}\\ x+\dfrac{1}{5}=\dfrac{59}{30}\\ x=\dfrac{59}{30}-\dfrac{1}{5}\\ x=\dfrac{53}{30}\)
25 tháng 3 2017
2) \(\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}\\ \dfrac{2}{5}+x=\dfrac{11}{12}-\dfrac{2}{3}\\ \dfrac{2}{5}+x=\dfrac{11}{12}-\dfrac{8}{12}\\ \dfrac{2}{5}+x=\dfrac{1}{4}\\ x=\dfrac{1}{4}-\dfrac{2}{5}\\ x=\dfrac{-3}{20}\)
2 tháng 5 2017
a) \(\left(2x-3\right)\left(6-2x\right)=0\)
\(\circledast\)TH1: \(2x-3=0\\ 2x=0+3\\ 2x=3\\ x=\dfrac{3}{2}\)
\(\circledast\)TH2: \(6-2x=0\\ 2x=6-0\\ 2x=6\\ x=\dfrac{6}{2}=3\)
Vậy \(x\in\left\{\dfrac{3}{2};3\right\}\).
b) \(\dfrac{1}{3}x+\dfrac{2}{5}\left(x-1\right)=0\)
\(\dfrac{1}{3}x=0-\dfrac{2}{5}\left(x-1\right)\)
\(\dfrac{1}{3}x=-\dfrac{2}{5}\left(x-1\right)\)
\(-\dfrac{2}{5}-\dfrac{1}{3}=-x\left(x-1\right)\)
\(-\dfrac{11}{15}=-x\left(x-1\right)\)
\(\Rightarrow x=1.491631652\)
Vậy \(x=1.491631652\)
c) \(\left(3x-1\right)\left(-\dfrac{1}{2}x+5\right)=0\)
\(\circledast\)TH1: \(3x-1=0\\ 3x=0+1\\ 3x=1\\ x=\dfrac{1}{3}\)
\(\circledast\)TH2: \(-\dfrac{1}{2}x+5=0\\ -\dfrac{1}{2}x=0-5\\ -\dfrac{1}{2}x=-5\\ x=-5:-\dfrac{1}{2}\\ x=10\)
Vậy \(x\in\left\{\dfrac{1}{3};10\right\}\).
d) \(\dfrac{x}{5}=\dfrac{2}{3}\\ x=\dfrac{5\cdot2}{3}\\ x=\dfrac{10}{3}\)
Vậy \(x=\dfrac{10}{3}\).
e) \(\dfrac{x}{3}-\dfrac{1}{2}=\dfrac{1}{5}\\ \)
\(\dfrac{x}{3}=\dfrac{1}{5}+\dfrac{1}{2}\)
\(\dfrac{x}{3}=\dfrac{7}{10}\)
\(x=\dfrac{3\cdot7}{10}\)
\(x=\dfrac{21}{10}\)
Vậy \(x=\dfrac{21}{10}\).
f) \(\dfrac{x}{5}-\dfrac{1}{2}=\dfrac{6}{10}\)
\(\dfrac{x}{5}=\dfrac{6}{10}+\dfrac{1}{2}\)
\(\dfrac{x}{5}=\dfrac{11}{10}\)
\(x=\dfrac{5\cdot11}{10}\)
\(x=\dfrac{55}{10}=\dfrac{11}{2}\)
Vậy \(x=\dfrac{11}{2}\).
g) \(\dfrac{x+3}{15}=\dfrac{1}{3}\\ x+3=\dfrac{15}{3}=5\\ x=5-3\\ x=2\)
Vậy \(x=2\).
h) \(\dfrac{x-12}{4}=\dfrac{1}{2}\\ x-12=\dfrac{4}{2}=2\\ x=2+12\\ x=14\)
Vậy \(x=14\).
21 tháng 4 2017
tìm x a)
\(\dfrac{7}{2}\)-\(\left(x+\dfrac{7}{10}\right)\): \(\dfrac{6}{5}\) = \(\dfrac{-5}{4}\)
\(\left(x+\dfrac{7}{10}\right)\): \(\dfrac{6}{5}\) = \(\dfrac{-5}{4}\) + \(\dfrac{7}{2}\)
\(\left(x+\dfrac{7}{10}\right)\): \(\dfrac{6}{5}\) = \(\dfrac{-5}{12}+\dfrac{7}{12}\)
\(\left(x+\dfrac{7}{10}\right)\): \(\dfrac{6}{5}\) = \(\dfrac{-12}{12}=1\)
\(x+\dfrac{7}{10}\)= 1 . \(\dfrac{6}{5}\)
*Rồi tự làm phần tt đi
\(75\%x-\dfrac{2}{5}x=\dfrac{3}{10}\)
\(\dfrac{75}{100}x-\dfrac{2}{5}x=\dfrac{3}{5}\)
\(\dfrac{75}{100}x-\dfrac{40}{100}x=\dfrac{60}{50}\)
\(x.\left(\dfrac{75}{100}-\dfrac{40}{100}\right)=\dfrac{60}{100}\)
\(x.\dfrac{35}{100}=\dfrac{60}{100}\)
\(\Rightarrow x=\dfrac{60}{100}:\dfrac{35}{100}\)
\(\Rightarrow x=\dfrac{12}{7}\)
75%x−25x=310
\(\dfrac{3}{4}\)x - \(\dfrac{2}{5}\) x = \(\dfrac{3}{10}\)
x ( \(\dfrac{3}{4}-\dfrac{2}{5}\)) = \(\dfrac{3}{10}\)
x (\(\dfrac{15}{20}-\dfrac{8}{20}\)) = \(\dfrac{3}{10}\)
x . \(\dfrac{7}{20}\) = \(\dfrac{3}{10}\)
x =\(\dfrac{3}{10}:\dfrac{7}{20}\)
x= \(\dfrac{3}{10}.\dfrac{20}{7}\)
x = \(\dfrac{3}{1}:\dfrac{2}{7}\)
x = \(\dfrac{6}{7}\)