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23 tháng 9 2018

4(x+2)=289-41

4(x+2)=248

x+2=248:4

x+2=62

x=62-2

x=60

23 tháng 9 2018

289 - 4 (x+2)=41

4(x+2)=248

x+2=62

x=60

=.= hok tốt!!

1 tháng 12 2023

1) $(-81)\cdot27-3^4\cdot(-77)$

$=(-81)\cdot27-81\cdot(-77)$

$=-81\cdot[27+(-77)]$

$=-81\cdot(27-77)$

$=-81\cdot(-50)$

$=81\cdot50$

$=4050$

2) $(-16)\cdot32-(-4)^2\cdot18$

$=(-16)\cdot32-16\cdot18$

$=-16\cdot(32+18)$

$=-16\cdot50$

$=-800$

3) $(-2)^4\cdot289-16\cdot189$

$=16\cdot289+16\cdot(-189)$

$=16\cdot[289+(-189)]$

$=16\cdot(289-189)$

$=16\cdot100$

$=1600$

4) $41\cdot(-18)+41\cdot(-81)-41$

$=1\cdot(-18)+41\cdot(-81)+41\cdot(-1)$

$=41\cdot[(-18)+(-81)+(-1)]$

$=41\cdot(-18-81-1)$

$=41\cdot(-99-1)$

$=41\cdot(-100)$

$=-4100$

5) $17\cdot(-37)-23\cdot37-46\cdot(-37)$

$=17\cdot(-37)+23\cdot(-37)-46\cdot(-37)$

$=-37\cdot(17+23-46)$

$=-37\cdot(40-46)$

$=-37\cdot(-6)$

$=37\cdot6$

$=222$

6) $-48+48\cdot(-78)+48\cdot(-21)$

$=48\cdot(-1)+48\cdot(-78)+48\cdot(-21)$

$=48\cdot[(-1)+(-78)+(-21)]$

$=48\cdot(-1-78-21)$

$=48\cdot(-79-21)$

$=48\cdot(-100)$

$=-4800$

7) $29\cdot(-13)+27\cdot(-29)+(-14)\cdot(-29)$

$=-29\cdot13+27\cdot(-29)+(-14)\cdot(-29)$

$=-29\cdot[13+27+(-14)]$

$=-29\cdot(40-14)$

$=-29\cdot26$

$=-754$

$\text{#}Toru$

a: \(=\dfrac{3\left(\dfrac{1}{41}-\dfrac{4}{47}+\dfrac{9}{53}\right)}{4\left(\dfrac{1}{41}-\dfrac{4}{47}+\dfrac{9}{53}\right)}+\dfrac{-\dfrac{1}{4}\cdot\dfrac{-2}{3}-\dfrac{3}{4}:\dfrac{1}{6}}{\dfrac{3}{2}\cdot\left(\dfrac{-2}{3}-\dfrac{3}{4}\cdot\dfrac{-2}{3}\right)}\)

\(=\dfrac{3}{4}+\dfrac{\dfrac{2}{12}-\dfrac{9}{2}}{\dfrac{3}{2}\cdot\dfrac{-1}{6}}=\dfrac{3}{4}+\dfrac{-13}{3}:\dfrac{-3}{12}\)

\(=\dfrac{3}{4}+\dfrac{13}{3}\cdot\dfrac{12}{3}=\dfrac{3}{4}+\dfrac{156}{9}=\dfrac{217}{12}\)

b: \(A=158\left(\dfrac{12\left(1-\dfrac{1}{7}-\dfrac{1}{289}-\dfrac{1}{85}\right)}{4\left(1-\dfrac{1}{7}-\dfrac{1}{289}-\dfrac{1}{85}\right)}:\dfrac{5\left(1+\dfrac{1}{13}+\dfrac{1}{169}+\dfrac{1}{91}\right)}{6\left(1+\dfrac{1}{13}+\dfrac{1}{169}+\dfrac{1}{91}\right)}\right)\cdot\dfrac{50550505}{711711711}\)

\(=158\cdot\left(3\cdot\dfrac{6}{5}\right)\cdot\dfrac{50550505}{711711711}\)

\(\simeq40.39\)

21 tháng 6 2017

a) \(\left(x-1\right)^3=125\)

\(\Leftrightarrow\left(x-1\right)^3=5^3\)

\(\Leftrightarrow x-1=5\)

\(\Leftrightarrow x=5+1\)

\(\Leftrightarrow x=6\)

Vậy \(x=6\)

b) \(2^{x+2}-2^x=96\)

\(\Leftrightarrow\left(2^2-1\right)\cdot2^x=96\)

\(\Leftrightarrow\left(4-1\right)\cdot2^x=96\)

\(\Leftrightarrow3\cdot2^x=96\)

\(\Leftrightarrow2^x=32\)

\(\Leftrightarrow2^x=2^5\)

\(\Leftrightarrow x=5\)

Vậy \(x=5\)

c) \(\left(2x+1\right)^3=343\)

\(\Leftrightarrow\left(2x+1\right)^3=7^3\)

\(\Leftrightarrow2x+1=7\)

\(\Leftrightarrow2x=7-1\)

\(\Leftrightarrow2x=6\)

\(\Leftrightarrow x=3\)

Vậy \(x=3\)

d) \(720:\left[41-\left(2x-5\right)\right]=2^3\cdot5\)

\(\Leftrightarrow720:\left[41-\left(2x-5\right)\right]=2^3\cdot5\left(đk:x\ne23\right)\)

\(\Leftrightarrow720:\left(41-2x+5\right)=8\cdot5\)

\(\Leftrightarrow720:\left(46-2x\right)=40\)

\(\Leftrightarrow\dfrac{720}{46-2x}=40\)

\(\Leftrightarrow\dfrac{720}{2\left(23-x\right)}=40\)

\(\Leftrightarrow\dfrac{360}{23-x}=40\)

\(\Leftrightarrow360=40\left(23-x\right)\)

\(\Leftrightarrow9=23-x\)

\(\Leftrightarrow x=23-9\)

\(\Leftrightarrow x=14\left(đk:x\ne23\right)\)

\(\Leftrightarrow x=14\)

Vậy \(x=14\)

e) \(2^x\cdot7=224\)

\(\Leftrightarrow7\cdot2^x=224\)

\(\Leftrightarrow2^x=32\)

\(\Leftrightarrow2^x=2^5\)

\(\Leftrightarrow x=5\)

Vậy \(x=5\)

f) \(\left(3x+5\right)^2=289\)

\(\Leftrightarrow3x+5=\pm17\)

\(\Leftrightarrow\left[{}\begin{matrix}3x+5=17\\3x+5=-17\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-\dfrac{22}{3}\end{matrix}\right.\)

Vậy \(x_1=-\dfrac{22}{3};x_2=4\)

21 tháng 6 2017

a)\(\left(x-1\right)^3=125\Leftrightarrow\left(x-1\right)^3=5^3\Leftrightarrow x-1=5\Leftrightarrow x=6\)b)\(2^{x+2}-2^x=96\Leftrightarrow2^x.2^2-2^x=96\Leftrightarrow2^x\left(2^2-1\right)=96\Leftrightarrow2^x.3=96\Leftrightarrow2^x=32\Leftrightarrow x=5\)c)\(\left(2x-1\right)^3=343\Leftrightarrow\left(2x-1\right)^3=7^3\Leftrightarrow2x-1=7\Rightarrow2x=8\Rightarrow x=4\)d)\(720:\left[41-\left(2x-5\right)\right]=2^3.5\)

\(720:\left[41-\left(2x-5\right)\right]=40\Leftrightarrow\left[41-\left(2x-5\right)\right]=720:40=18\)

\(\Leftrightarrow41-2x+5=18\Leftrightarrow36-2x=18\Leftrightarrow2x=18\Leftrightarrow x=9\)

e)\(2^x.7=224\Leftrightarrow2^x=224:7=32\Leftrightarrow2^x=2^5\Leftrightarrow x=5\)

f) \(\left(3x+5\right)^2=289\Leftrightarrow\left(3x+5\right)=17^2\Leftrightarrow3x+5=17\Leftrightarrow3x=12\Leftrightarrow x=4\)

6 tháng 4 2022

vì a chia 289 dư 39 nên 289-39=250\(\vdots\)a và 39<a<250

 a chia 289 dư 39 nên 241-41=200\(\vdots \)a và 41<a<200

=>a\(\in \)ƯC(250,200) và 39<a<200

Mà ƯCLN(250,200)=50

=>a\(\in\)Ư(50)={0,50,100,150,200,...}

Vì 39<a<200 nên a\(\in\){50,100,150}

22 tháng 11 2015

a)-Ix-3I+16=4

-Ix-3I=4-16

-Ix-3I=-12

-IxI=-12+3

-IxI=-9

x=-9

b)3-(17-x)=289-(36+289)

3-(17-x)=289-325

3-(17-x)=-36

(17-x)=3-(-36)

(17-x)=39

x=17-39

x=-22

c)25-(x+5)=415-(15-415)

25-(x+5)=415-(-400)

25-(x+5)=815

(x+5)=25-815

(x+5)=-790

x=(-790)-5

x=-795

d)34+(21-x)=(3747-30)-3746

34+(21-x)=3717-3746

34+(21-x)=-29

31+x=21-(-29)

31+x=50

x=50-31

x=19