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28 tháng 9 2021

\(3^{x-2}=27\)

\(3^{x-2}=3^3\)

\(\Rightarrow x-2=3\)

\(x=5\)

28 tháng 9 2021

\(3^{x-3}+16=25\)

\(3^{x-3}=9\)

\(3^{x-3}=3^2\)

\(\Rightarrow x-3=2\)

\(x=5\)

27 tháng 3 2020

mai nah

28 tháng 3 2020

cậu giúp mk là đc

Câu 1: 

a: =>-2x-x+17=34+x-25

=>-3x+17=x+9

=>-4x=-8

hay x=2

b: =>17x+16x+27=2x+43

=>33x+27=2x+43

=>31x=16

hay x=16/31

c: =>-2x-3x+51=34+2x-50

=>-5x+51=2x-16

=>-7x=-67

hay x=67/7

e: 3x-32>-5x+1

=>8x>33

hay x>33/8

11 tháng 7 2019

a) (x - 1/2)2 = 4

<=> (x - 1/2)2 = 22

<=> x - 1/2 = -2; 2

<=> x - 1/2 = 2 hoặc x - 1/2 = -2

       x = 2 + 1/2         x = -2 + 1/2

       x = 5/2               x = -3/2

=> x = 5/2 hoặc x = -3/2

b) 10/1/2 - (x + 1/3)2 = 1/1/2

<=> -(x + 1/3)2 = 1/1/2 - 10/1/2

<=> -(x + 1/3)2 = 1/2 - 5

<=> -(x + 1/3)2 = -5.2 + 1/2

<=> -(x + 1/3)2 = -9/2

<=> (x + 1/3)2 = 9/2

<=> x + 1/3 = \(\sqrt{\frac{9}{2}}\)  hoặc x + 1/3 = \(-\sqrt{\frac{9}{2}}\)

       x = \(\frac{3\sqrt{2}}{2}\) - 1/3         x = \(-\frac{3\sqrt{2}}{2}\) -1/3

=> x = \(\frac{3\sqrt{2}}{2}\) - 1/3 hoặc x = \(-\frac{3\sqrt{2}}{2}\) -1/3

c) (x - 1/5)2 + 17/25 = 26/25

<=> (x - 1/5)2 = 26/25 - 17/25

<=> (x - 1/5)2 = (3/5)2

<=> x - 1/5 = -3/5; 3/5

<=> x - 1/5 = 3/5 hoặc x - 1/5 = -3/5

       x = 3/5 + 1/5         x = -3/5 + 1/5

       x = 4/5                  x = -2/5

=> x = 4/5 hoặc x = -2/5

2 tháng 6 2017

a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)

\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)

\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)

b) \(\dfrac{39}{7}:x=13\)

\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)

c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)

\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)

\(\dfrac{14}{5}x=34+50=84\)

\(x=\dfrac{84}{\dfrac{14}{5}}=30\)

d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)

e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)

\(\dfrac{1}{6}x=\dfrac{5}{12}\)

\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)

g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)

\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)

\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)

\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)

\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)

h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)

\(x=1\)

Mỏi tay woa bn làm nốt nha!!

giúp mik đi mà, gấp lắm, mik phải đi học ngay r, huhuhu

15 tháng 4 2018

\(a)\frac{5}{8}-x=2\frac{1}{6}\)

\(\Rightarrow\frac{5}{8}-x=\frac{13}{6}\)

\(\Rightarrow x=\frac{5}{8}-\frac{13}{6}\)

\(\Rightarrow x=\frac{15}{24}-\frac{52}{24}\)

\(\Rightarrow x=-\frac{37}{24}\)

\(b)\) \(\frac{4}{9}:x=-\frac{1}{3}+1\frac{1}{6}\)

\(\Rightarrow\frac{4}{9}:x=-\frac{1}{3}+\frac{7}{6}\)

\(\Rightarrow\frac{4}{9}:x=-\frac{2}{6}+\frac{7}{6}\)

\(\Rightarrow\frac{4}{9}:x=\frac{5}{6}\)

\(\Rightarrow x=\frac{4}{9}:\frac{5}{6}\)

\(\Rightarrow x=\frac{4}{9}.\frac{6}{5}\)

\(\Rightarrow x=\frac{8}{15}\)

\(c)\left(3x-2\right)^3=-\frac{1}{27}\)

\(\Rightarrow3x-2=-\frac{1}{3}\)

\(\Rightarrow3x=-\frac{1}{3}+2\)

\(\Rightarrow3x=-\frac{1}{3}+\frac{6}{3}\)

\(\Rightarrow3x=\frac{5}{3}\)

\(\Rightarrow x=\frac{5}{3}:3\)

\(\Rightarrow x=\frac{5}{9}\)

d ) và e ) tự làm 

Chúc bạn học tốt !!! 

15 tháng 4 2018
5/8-x=21/6 x=5/8-21/6 x=-23/8 Vậy x=-23/8 b, 4/9:x=-1/3+11/6 4/9:x= 3/2 x= 4/9:3/2
19 tháng 3 2020

Bài 2:

a) \(\frac{4^2\cdot25^2+16\cdot125}{2^3\cdot5^2}=\frac{2^4\cdot5^4+2^4\cdot5^3}{2^3\cdot5^2}=\frac{2^4\cdot5^3\cdot\left(5+1\right)}{2^3\cdot5^2}=2\cdot5\cdot6=60\)

b) \(\frac{6^8\cdot2^4-4^5\cdot18^4}{27^3\cdot8^4-3^9\cdot2^{13}}=\frac{2^8\cdot3^8\cdot2^4-2^{10}\cdot2^4\cdot3^8}{3^9\cdot2^{12}-3^9\cdot2^{13}}=\frac{2^{12}\cdot3^8-2^{14}\cdot3^8}{3^9\cdot2^{12}\cdot\left(1-2\right)}=\frac{2^{12}\cdot3^8\cdot\left(1-2^2\right)}{3^9\cdot2^{12}\cdot\left(-1\right)}\)

\(=\frac{2^2-1}{3}=\frac{3}{3}=1\)

Thanks bạn .