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2 tháng 1 2019

\(3+2\left|x-2\right|=2^3-\left(-1\right)\)

\(\Rightarrow3+2\left|x-2\right|=8+1\)

\(\Rightarrow2\left|x-2\right|=9-3\)

\(\Rightarrow2\left|x-2\right|=6\)

\(\Rightarrow\left|x-2\right|=6\div2\)

\(\Rightarrow\left|x-2\right|=3\)

\(\Rightarrow\orbr{\begin{cases}x-2=-3\\x-2=3\end{cases}}\)

\(\text{Trường hợp : }x-2=-3\)

\(\Rightarrow x=-3+2\)

\(\Rightarrow x=-1\)

\(\text{Trường hợp : }x-2=3\)

\(\Rightarrow x=3+2\)

\(\Rightarrow x=5\)

\(\text{Vậy }x\in\left\{-1;5\right\}\)

2 tháng 1 2019

\(3+2.\left|x-2\right|=2^3-\left(-1\right)\)

\(\Leftrightarrow3+2.\left|x-2\right|=2^3+1\)

\(\Leftrightarrow3+2.\left|x-2\right|=8+1\)

\(\Leftrightarrow3+2.\left|x-2\right|=9\)

\(\Leftrightarrow2.\left|x-2\right|=9-3\)

\(\Leftrightarrow2.\left|x-2\right|=6\)

\(\Leftrightarrow\left|x-2\right|=6:2\)

\(\Leftrightarrow\left|x-2\right|=3\)

Xét 2 TH:

TH1: 

x - 2 = -3

x      = -3 + 2

x      = -1

TH2:

x - 2 = 3

x      = 3 + 2

x      = 5

\(\Rightarrow\orbr{\begin{cases}x=-1\\x=5\end{cases}}\)

7 tháng 8 2019

\(1,\frac{2}{3}+\frac{4}{9}+\frac{1}{5}+\frac{2}{15}+\frac{3}{2}-\frac{17}{18}\)

\(< =>\frac{4}{9}+\frac{3}{2}+\left(\frac{2}{3}+\frac{1}{5}+\frac{2}{15}\right)-\frac{17}{18}\)

\(< =>\frac{8}{18}+\frac{27}{18}+\left(\frac{10}{15}+\frac{3}{15}+\frac{2}{15}\right)-\frac{17}{18}\)

\(< =>\frac{35}{18}+1-\frac{17}{18}\)

\(< =>\frac{53}{18}-\frac{17}{18}\)

\(< =>2\)

\(2,\frac{13}{28}\cdot\frac{5}{12}-\frac{5}{28}\cdot\frac{1}{12}\)

\(< =>\left(\frac{13}{28}-\frac{5}{28}\right)\cdot\left(\frac{5}{12}-\frac{1}{12}\right)\)

\(< =>\frac{2}{7}\cdot\frac{1}{3}\)

\(< =>\frac{2}{21}\)

\(3,\frac{19}{4}\cdot\frac{15}{23}-\frac{15}{4}\cdot\frac{7}{23}+\frac{15}{4}\cdot\frac{11}{23}\)

\(< =>\frac{285}{92}-\frac{105}{92}+\frac{165}{92}\)

\(< =>\frac{15}{4}\)

8 tháng 8 2019

cảm ơn bạn nha bạn chắc chăn đúng không

8 tháng 3 2023

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17 tháng 2 2020

\(\frac{x-23}{24}+\frac{x-23}{25}=\frac{x-23}{26}\)

\(\Leftrightarrow\frac{x-23}{24}+\frac{x-23}{25}-\frac{x-23}{26}=0\)

\(\Leftrightarrow\left(x-23\right)\left(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}\right)=0\)

\(\Leftrightarrow x-23=0\left(vì\frac{1}{24}+\frac{1}{25}-\frac{1}{26}\ne0\right)\)

\(\Leftrightarrow x=23\)

vậy................

\(\frac{201-x}{99}+\frac{203-x}{97}+\frac{205-x}{95}+3=0\)

\(\Leftrightarrow\left(\frac{201-x}{99}+1\right)+\left(\frac{203-x}{97}+1\right)+\left(\frac{205-x}{95}+1\right)=0\)

\(\Leftrightarrow\frac{300-x}{99}+\frac{300-x}{97}+\frac{300-x}{95}=0\)

\(\Leftrightarrow\left(300-x\right)\left(\frac{1}{99}+\frac{1}{97}+\frac{1}{95}\right)=0\)

\(\Leftrightarrow300-x=0\left(vì\frac{1}{99}+\frac{1}{97}+\frac{1}{95}>0\right)\)

\(\Leftrightarrow x=300\)

vậy..........

9 tháng 7 2023

a) Đặt: \(A=1+2^2+2^3+...+2^{10}\)

\(\Rightarrow2A=2\left(1+2^2+2^3+...+2^9+2^{10}\right)\)

\(\Rightarrow2A=2+2^3+2^4+...+2^{10}+2^{11}\)

\(\Rightarrow2A-A=\left(2+2^3+2^4+...+2^{10}+2^{11}\right)-\left(1+2^2+2^3+...+2^{10}\right)\)

\(\Rightarrow A=\left(2^3-2^3\right)+\left(2^4-2^4\right)+...+\left(2-1\right)+\left(2^{11}-2^2\right)\)

\(\Rightarrow A=0+0+...+1+\left(2^{11}-2^2\right)\)

\(\Rightarrow A=1+2^{11}-2^2=1+2048-4=2045\)

Vậy: \(1+2^2+2^3+...+2^{10}=2045\)

b) 

a] \(60-3\left(x-1\right)=2^3\cdot3\)

\(\Rightarrow60-3\left(x-1\right)=24\)

\(\Rightarrow3\left(x-1\right)=36\)

\(\Rightarrow x-1=12\)

\(\Rightarrow x=13\)

b] \(\left(3x-2\right)^3=2\cdot2^5\)

\(\Rightarrow\left(3x-2\right)^3=2^6\)

\(\Rightarrow\left(3x-2\right)^3=\left(2^2\right)^3\)

\(\Rightarrow3x-2=2^2\)

\(\Rightarrow3x=6\)

\(x=2\)

c] \(5^{x+1}-5^x=500\)

\(\Rightarrow5^x\left(5-1\right)=500\)

\(\Rightarrow5^x\cdot4=500\)

\(\Rightarrow5^x=125\)

\(\Rightarrow5^x=5^3\)

\(\Rightarrow x=3\)

d] \(x^2=x^4\)

\(\Rightarrow x=x^2\)

\(\Rightarrow x-x^2=0\)

\(\Rightarrow x\left(1-x\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\1-x=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)

9 tháng 7 2023

giúp mình đi các bạn

 

22 tháng 8 2018

1. Tính:

a) 23 + 24 - ( 65 x 2 - 4 ) x 4 + 66 + 44 - ( 54 : 9 x 9 : 9 + 45 ) : 1 + 1 - 1 x ( 23 + 23 - 23 x 2 +1 ) = 51

b) 4444444444444444444444444444444444444444444444444444444444444444444 : 1

= 4444444444444444444444444444444444444444444444444444444444444444444

c) 30 = 0

d) 1/1 = 1

e)

22 tháng 8 2018

a) - 530

b) 44444444444444444444444444444444444444444444444444444444444444444444

c) 0

d) 1

e) Em là em

5 tháng 8 2016

a)x=0+45

x=45

b)x=23:23=1

x=42-1

x=41

c)x=613+5=618

x=618:6

x=13

9 tháng 9 2016

a)x=45

b)x=41

c)x=103

d)x=111

e)x=60

g)x=5

h)x=3x=26