\(^x\) + (-4) . 5\(^{x+4}\) - 3 . 5\...">
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11 tháng 9 2017

A = \(\frac{5}{4}.\left(5-\frac{4}{3}\right).\frac{1}{11}\)

A = \(\frac{5}{44}\left(5-\frac{4}{3}\right)\)

A = \(\frac{25}{44}-\frac{5}{33}\)

A = \(\frac{25.3}{4.11.3}-\frac{5.4}{3.11.4}\)

A = \(\frac{75}{132}-\frac{20}{132}\)

A = \(\frac{55}{132}\)

B = \(\frac{3}{4}:\left(-12\right).\left(-\frac{2}{3}\right)\)

B = \(\frac{-1}{16}.\left(-\frac{2}{3}\right)\)

B = \(\frac{1}{24}\)

C = \(\frac{5}{4}:\left(-15\right).\left(-\frac{2}{5}\right)\)

C = \(\frac{-1}{12}.\left(-\frac{2}{5}\right)\)

C = \(\frac{1}{30}\)

D = \(\left(-3\right).\left(\frac{2}{3}-\frac{5}{4}\right):\left(-7\right)\)

D = \(\frac{3}{7}.\left(\frac{8}{12}-\frac{15}{12}\right)\)

D = \(\frac{3}{7}.\left(-\frac{7}{12}\right)\)

D = \(\frac{-3}{12}\)

D = \(\frac{-1}{4}\)

18 tháng 6 2018

Giải:

a) \(\dfrac{1}{3}x+\dfrac{1}{5}-\dfrac{1}{2}x=1\dfrac{1}{4}\)

\(\Leftrightarrow\dfrac{1}{5}-\dfrac{1}{6}x=\dfrac{5}{4}\)

\(\Leftrightarrow\dfrac{1}{6}x=\dfrac{-21}{20}\)

\(\Leftrightarrow x=\dfrac{-63}{10}\)

Vậy ...

b) \(\dfrac{3}{2}\left(x+\dfrac{1}{2}\right)-\dfrac{1}{8}x=\dfrac{1}{4}\)

\(\Leftrightarrow\dfrac{3}{2}x+\dfrac{3}{4}-\dfrac{1}{8}x=\dfrac{1}{4}\)

\(\Leftrightarrow\dfrac{11}{8}x=\dfrac{-1}{2}\)

\(\Leftrightarrow x=\dfrac{-4}{11}\)

Vậy ...

Các câu sau làm tương tự câu b)

14 tháng 2 2018

a) \(2\left(4x-30\right)-3\left(x+5\right)+4\left(x-10\right)=5\left(x+2\right)\)

\(\Leftrightarrow8x-60-3x+15+4x-40=5x+10\)

\(\Leftrightarrow9x-35=5x+10\)

\(\Leftrightarrow9x-5x=10+35\)

\(\Leftrightarrow4x=45\)

\(\Leftrightarrow x=\dfrac{45}{4}=11,25\)

b) \(\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}\left(6x+1\right)\)

\(\Leftrightarrow\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=4x+\dfrac{2}{3}\)

\(\Leftrightarrow\dfrac{31}{60}+x=4x+\dfrac{2}{3}\)

\(\Leftrightarrow\dfrac{31}{60}-\dfrac{2}{3}=4x-x\)

\(\Leftrightarrow3x=\dfrac{1}{60}\)

\(\Leftrightarrow x=\dfrac{1}{180}\)

c) \(\dfrac{7}{3}-\left(2x-\dfrac{1}{3}\right)=\left(-2\dfrac{1}{6}+1\dfrac{1}{2}\right):0,25\)

\(\Leftrightarrow\dfrac{7}{3}-2x+\dfrac{1}{3}=-1\dfrac{2}{3}:\dfrac{1}{4}\)

\(\Leftrightarrow\dfrac{8}{3}-2x=\dfrac{-5}{3}.4\)

\(\Leftrightarrow\dfrac{8}{3}-2x=\dfrac{-20}{3}\)

\(\Leftrightarrow2x=\dfrac{8}{3}+\dfrac{20}{3}\)

\(\Leftrightarrow2x=\dfrac{28}{3}\)

\(\Leftrightarrow x=4\dfrac{2}{3}\)

d) \(0,75+\dfrac{5}{9}:x=5\dfrac{1}{2}\)

\(\Leftrightarrow\dfrac{3}{4}+\dfrac{5}{9}:x=\dfrac{11}{2}\)

\(\Leftrightarrow\dfrac{5}{9}:x=\dfrac{11}{2}-\dfrac{3}{4}\)

\(\Leftrightarrow\dfrac{5}{9}:x=\dfrac{19}{4}\)

\(\Leftrightarrow x=\dfrac{5}{9}:\dfrac{19}{4}\)

\(\Leftrightarrow x=\dfrac{20}{171}\)

16 tháng 9 2017

a) \(x:\left(\frac{3}{4}\right)^3=\left(\frac{3}{4}\right)^2\)

\(x=\left(\frac{3}{4}\right)^2.\left(\frac{3}{4}\right)^3\)

\(x=\left(\frac{3}{4}\right)^5\)

\(x=\frac{243}{1024}\)

vay \(x=\frac{243}{1024}\)

b) \(\left(\frac{2}{5}\right)^5.x=\left(\frac{2}{5}\right)^8\)

\(x=\left(\frac{2}{5}\right)^8:\left(\frac{2}{5}\right)^5\)

\(x=\left(\frac{2}{5}\right)^3\)

\(x=\frac{8}{125}\)

vay \(x=\frac{8}{125}\)

4) \(\left(0,36\right)^8=\left(0,6^2\right)^8=\left(0,6\right)^{16}\)

\(\left(0,216\right)^4=\left(0,6^3\right)^4=\left(0,6\right)^{12}\)

5) a) \(\left(3,5\right)^3=42,875\)

b) \(\left(-\frac{4}{11}\right)^2=\frac{16}{121}\)

c) \(\left(0,5\right)^4.6^4=3^4=81\)

d) \(\left(-\frac{1}{3}\right)^5:\left(\frac{1}{6}\right)^5=\left(-2\right)^5=-32\)

30 tháng 8 2019

1) -2/3

1: \(\Leftrightarrow3x+4=2\)

=>3x=-2

=>x=-2/3

2: \(\Leftrightarrow7x-7=6x-30\)

=>x=-23

3: =>\(5x-5=3x+9\)

=>2x=14

=>x=7

4: =>9x+15=14x+7

=>-5x=-8

=>x=8/5

26 tháng 7 2018

a) \(\dfrac{x}{48}=-\dfrac{4}{7}\Rightarrow x=-\dfrac{192}{7}\)

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

\(\Rightarrow x=\dfrac{1}{5}\)

c) \(2\left|x-1\right|^2=72\Rightarrow\left|x-1\right|^2=36\)

\(\Rightarrow\left|x-1\right|=6\)

TH1: x - 1 = -6 => x = -5

TH2: x - 1 = 6 => x = 7

e) \(\dfrac{x}{2,5}=\dfrac{4}{5}\Rightarrow x=2\)

f) | x - 2 | = 1 + 4 = 5

TH1: x - 2 = -5 => x = -3

TH2: x - 2 = 5 => x = 7

26 tháng 7 2018

a) \(\dfrac{x}{48}=\dfrac{-4}{7}\)

⇒ x.7=48.(-4)

7x = -192

x=\(\dfrac{-192}{7}\) Vậy x=\(\dfrac{-192}{7}\)

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

\(\left(x+\dfrac{4}{5}\right)=\dfrac{3}{5}+\dfrac{2}{5}\)

\(x+\dfrac{4}{5}=1\)

\(x=1-\dfrac{4}{5}\)

\(x=\dfrac{1}{5}\)

c) chưa từng gặp dạng với giá trị tuyệt đối sory

d) \(\dfrac{1}{6}x-\dfrac{2}{3}=2\)

\(\dfrac{1}{6}x=2+\dfrac{2}{3}\)

\(\dfrac{1}{6}x=\dfrac{8}{3}\)

\(x=\dfrac{8}{3}:\dfrac{1}{6}\)

\(x=16\)

e) \(\dfrac{x}{2,5}=\dfrac{4}{5}\)

=> x.5 = 4.2,5

5x=10

x=10:5

x=2

f) |x-2|-4=1

|x-2|=1+4

|x-2|=5

=>\(\left[{}\begin{matrix}x-2=5\\x-2=-5\end{matrix}\right.\) =>\(\left[{}\begin{matrix}x=5+2\\x=-5+2\end{matrix}\right.\) =>\(\left[{}\begin{matrix}x=7\\x=-3\end{matrix}\right.\)

đôi khi cũng có sai sót , hãy xem lại thật kĩ

5 tháng 8 2018

a. \(\dfrac{-39}{7}:x=26\)

x = \(\dfrac{-39}{7}:26\)

x = \(\dfrac{-3}{14}\)

b. \(x:\dfrac{13}{5}=\dfrac{7}{4}\)

x = \(\dfrac{7}{4}.\dfrac{13}{5}\)

x = \(\dfrac{91}{20}\)

c. x = \(\dfrac{-3}{5}-\dfrac{1}{2}\)

x = \(\dfrac{-11}{10}\)

d. \(x-\dfrac{3}{4}=\dfrac{9}{4}\)

x = \(\dfrac{9}{4}+\dfrac{3}{4}\)

x = 3

e. \(\dfrac{7}{8}:x=\dfrac{14}{3}\)

x = \(\dfrac{7}{8}:\dfrac{14}{3}\)

x = \(\dfrac{3}{16}\)

f. \(x:\dfrac{8}{3}=\dfrac{13}{3}\)

x = \(\dfrac{13}{3}.\dfrac{8}{3}\)

x = \(\dfrac{104}{9}\)

g. x = \(\dfrac{4}{10}-\dfrac{2}{5}\)

x = 0

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