\(\frac{3}{2}-4\left(\frac{1}{4}-x\right)=\frac{2}{3}-7x\)

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24 tháng 7 2018

Giải:

a) \(\frac{1}{5}-\frac{2}{3}+2x=\frac{1}{2}\)

\(\Leftrightarrow2x=\frac{1}{2}-\left(\frac{1}{5}-\frac{2}{3}\right)\)

\(\Leftrightarrow2x=\frac{1}{2}-\frac{-7}{15}\)

\(\Leftrightarrow2x=\frac{11}{15}\)

\(\Leftrightarrow x=\frac{11}{15}:2\)

\(\Leftrightarrow x=\frac{11}{30}\)

b) \(4\left(\frac{1}{3}-3\right)+\frac{1}{2}=\frac{5}{6}+x\)

\(\Leftrightarrow\frac{-61}{6}=\frac{5}{6}+x\)

\(\Leftrightarrow x=\frac{-61}{6}-\frac{5}{6}\)

\(\Leftrightarrow x=\frac{-66}{6}=-11\)

22 tháng 8 2019

1,\(\frac{2}{9}.\left(x-\frac{9}{4}\right)+\frac{1}{2}=\frac{3}{7}.\left(7-\frac{1}{6}\right)+\frac{1}{3}\)

  \(\frac{2}{9}.\left(x-\frac{9}{4}\right)+\frac{1}{2}=\frac{3}{7}.\frac{41}{6}+\frac{1}{3}\)

\(\frac{2}{9}.\left(x-\frac{9}{4}\right)+\frac{1}{2}=\frac{41}{14}+\frac{1}{3}\)

 \(\frac{2}{9}.\left(x-\frac{9}{4}\right)+\frac{1}{2}=\frac{137}{42}\)

\(\frac{2}{9}.\left(x-\frac{9}{4}\right)=\frac{137}{42}-\frac{1}{2}\)

\(\frac{2}{9}.\left(x-\frac{9}{4}\right)=\frac{58}{21}\)

 \(\left(x-\frac{9}{4}\right)=\frac{5}{2}:\frac{2}{9}\)

\(\left(x-\frac{9}{4}\right)=\frac{45}{4}\)

\(x=\frac{45}{4}+\frac{9}{4}\)

\(x=\frac{27}{2}\)

22 tháng 8 2019

Bước cưối 58/21 minh man viết nhầm nên sai 

6 tháng 6 2016

a) (1/2(2/− 2x0

\(\Rightarrow\left[\begin{array}{nghiempt}x+\frac{1}{2}=0\\\frac{2}{3}-2x=0\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x=-\frac{1}{2}\\2x=\frac{2}{3}\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x=-\frac{1}{2}\\x=\frac{1}{3}\end{array}\right.\)

b) \(\left(x.6\frac{2}{7}+\frac{3}{7}\right).2\frac{1}{5}-\frac{3}{7}=-2\)

\(\Rightarrow\left(x.\frac{44}{7}+\frac{3}{7}\right).\frac{11}{5}=-2+\frac{3}{7}\)

\(\Rightarrow\left(x.\frac{44}{7}+\frac{3}{7}\right).\frac{11}{5}=-\frac{11}{7}\)

\(\Rightarrow x.\frac{44}{7}+\frac{3}{7}=-\frac{11}{7}:\frac{11}{5}=-\frac{11}{7}.\frac{5}{11}\)

\(\Rightarrow x.\frac{44}{7}+\frac{3}{7}=-\frac{5}{7}\)

\(\Rightarrow x.\frac{44}{7}=-\frac{5}{7}-\frac{3}{7}\)

\(\Rightarrow x.\frac{44}{7}=-\frac{8}{7}\)

\(\Rightarrow x=-\frac{8}{7}:\frac{44}{7}=-\frac{8}{7}.\frac{7}{44}\)

\(\Rightarrow x=-\frac{2}{11}\)

6 tháng 6 2016

c) \(x.3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)

\(\Rightarrow x\left(3\frac{1}{4}-\frac{7}{6}\right)=\frac{5}{12}+\frac{5}{3}\)

\(\Rightarrow x\left(\frac{13}{4}-\frac{7}{6}\right)=\frac{25}{12}\)

\(\Rightarrow x.\frac{25}{12}=\frac{25}{12}\)

\(\Rightarrow x=\frac{25}{12}:\frac{25}{12}\)

\(\Rightarrow x=1\)

d) \(5\frac{8}{17}:x+\left(-\frac{4}{17}\right):x+3\frac{1}{7}:17\frac{1}{3}=\frac{4}{11}\)

\(\Rightarrow\left(5\frac{8}{17}-\frac{4}{17}\right):x+\frac{22}{7}:\frac{52}{3}=\frac{4}{11}\)

\(\Rightarrow5\frac{4}{17}:x+\frac{33}{182}=\frac{4}{11}\)

\(\Rightarrow\frac{89}{17}:x=\frac{4}{11}-\frac{33}{182}\)

\(\Rightarrow\frac{89}{17}:x=\frac{365}{2002}\)

\(\Rightarrow x=\frac{89}{17}:\frac{365}{2002}\)

\(\Rightarrow x\approx28,7\) (số hơi lẻ)

e) \(\frac{17}{2}-\left|2x-\frac{3}{4}\right|=-\frac{7}{4}\)

\(\Rightarrow\left|2x-\frac{3}{4}\right|=\frac{17}{2}+\frac{7}{4}\)

\(\Rightarrow\left|2x-\frac{3}{4}\right|=\frac{41}{4}\)

\(\Rightarrow\left[\begin{array}{nghiempt}2x-\frac{3}{4}=\frac{41}{4}\\2x-\frac{3}{4}=-\frac{41}{4}\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}2x=11\\2x=-\frac{19}{2}\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x=\frac{11}{2}\\x=-\frac{19}{4}\end{array}\right.\)

Bài 1:Thực hiện phép tính\(a,75\%-1\frac{1}{2}+0,5:\frac{5}{12}-\left(\frac{-1}{2}\right)^2\)         \(b,\left(\frac{5}{7}.0,6-5:3\frac{1}{2}\right).\left(40\%-1,4\right).\left(-2\right)^3\)Bài 2: Tính nhanh                                               \(\left(\frac{-4}{5}+\frac{4}{3}\right)+\left(\frac{-5}{4}+\frac{14}{5}\right)-\frac{7}{3}\)Bài 3:Tìm x biết\(a,\frac{-2}{3}-\frac{1}{3}.\left(2x-5\right)=\frac{3}{2}\)   ...
Đọc tiếp

Bài 1:Thực hiện phép tính

\(a,75\%-1\frac{1}{2}+0,5:\frac{5}{12}-\left(\frac{-1}{2}\right)^2\)         \(b,\left(\frac{5}{7}.0,6-5:3\frac{1}{2}\right).\left(40\%-1,4\right).\left(-2\right)^3\)

Bài 2: Tính nhanh

                                               \(\left(\frac{-4}{5}+\frac{4}{3}\right)+\left(\frac{-5}{4}+\frac{14}{5}\right)-\frac{7}{3}\)

Bài 3:Tìm x biết

\(a,\frac{-2}{3}-\frac{1}{3}.\left(2x-5\right)=\frac{3}{2}\)      \(b,\frac{2}{5}.x+\frac{1}{2}=\frac{-3}{4}\)      \(\frac{1}{3}.x-8=\frac{1}{2}\)       \(x-\frac{1}{4}=\frac{5}{8}.\frac{2}{3}\)

Bài 4: Tìm x biết

\(a,\left(\frac{3}{4}.x+2\frac{1}{2}\right).\frac{-2}{3}=\frac{1}{8}\)                          \(b,\frac{1}{3}.x-0,5=0,75\)

Bài 5: Tìm x biết 

\(a,\frac{2}{5}+\frac{3}{5}.\left(3x-3,7\right)=-\frac{53}{10}\)       \(b,5,2.x+7\frac{2}{5}=6\frac{3}{4}\)       \(2,4:\left(\frac{-1}{2}-x\right)=1\frac{3}{5}\)

Bài 6:Tìm số tự nhiên x,biết: \(\left(x-5\right).\frac{30}{100}=\frac{20.x}{100}+5\)

Mik đang cần gấp giúp mik nha!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

4
4 tháng 5 2019

Dùng máy tính

4 tháng 5 2019

Nếu ko có máy tính thì sao?

18 tháng 3 2018

a) (7x - 11)3 = 25 x 52 + 200

     (7x - 11)3 = 800 + 200

     (7x - 11)3 = 1000

     (7x - 11)3 = 103

=>     7x - 11 = 10

=>            7x = 10 + 11

=>             7x = 21

=>                x =  3

b) \(3\frac{1}{3}x+16\frac{3}{4}=-13,25\)

                     \(3\frac{1}{3}x=-13,25-16\frac{3}{4}\)

                     \(\frac{10}{3}x=-30\)

                             \(x=-9\)

18 tháng 3 2018

a, x= 3

b, -9

23 tháng 7 2017

\(a;\)\(\left(x+\frac{1}{3}\right)^2=x+\frac{1}{3}\)

\(\Leftrightarrow\left(x+\frac{1}{3}\right)^2-\left(x+\frac{1}{3}\right)=0\)

\(\Leftrightarrow\left(x+\frac{1}{3}\right)\left(x+\frac{1}{3}-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{3}=0\\x+\frac{1}{3}-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{3}\\x=\frac{2}{3}\end{cases}}}\)

b)\(\left(x-\frac{1}{4}\right)^3=\left(x-\frac{1}{4}\right)^2\)

\(\Leftrightarrow\left(x-\frac{1}{4}\right)^3-\left(x-\frac{1}{4}\right)^2=0\)

\(\Leftrightarrow\left(x-\frac{1}{4}\right)^2\left(x-\frac{1}{4}-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}\left(x-\frac{1}{4}\right)^2=0\\\left(x-\frac{1}{4}-1\right)=0\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x-\frac{1}{4}=0\\x-\frac{5}{4}=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{4}\\x=\frac{5}{4}\end{cases}}}\)

23 tháng 7 2017


\(\left(x+\frac{1}{3}\right)^2-\left(x+\frac{1}{3}\right)\)=0
\(\left(x+\frac{1}{3}\right)\left(x+\frac{1}{3}-1\right)=0\)
\(\left(x+\frac{1}{3}\right)\left(x-\frac{2}{3}\right)=0\)
x=-1/3 hoặc x=2/3
b tương tự