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Nezuko Kamado
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Nguyễn Lê Phước Thịnh
29 tháng 10 2021 lúc 22:01

3: \(\left|x-\dfrac{3}{4}\right|-\dfrac{1}{2}=0\)

\(\Leftrightarrow\left|x-\dfrac{3}{4}\right|=\dfrac{1}{2}\)

\(\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{1}{2}\\x-\dfrac{3}{4}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=\dfrac{1}{4}\end{matrix}\right.\)

원회으Won Hoe Eu
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sói nguyễn
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Nguyễn Huy Tú
25 tháng 1 2022 lúc 14:07

1, bạn xem lại đề 

2, 15(x-3) + 8x-21 = 12(x+1) +120 

<=> 23x - 66 = 12x + 132 

<=> 11x = 198 <=> x = 198/11 

3, 10(3x+1) + 5 - 100 = 8(3x-1) - 6x - 4 

<=> 30x + 10 - 95 = 18x -12

<=> 12x = 73 <=> x = 73/12 

Lê Anh Tuấn
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Nguyễn Hoàng Minh
6 tháng 10 2021 lúc 20:34

\(b,=-\dfrac{40}{30}-\dfrac{12}{30}-\dfrac{45}{30}=-\dfrac{97}{30}\\ c,=\left(\dfrac{4}{5}+\dfrac{7}{10}\right)+\dfrac{2}{7}=\dfrac{3}{2}+\dfrac{2}{7}=\dfrac{25}{14}\\ d,=\dfrac{2}{3}+\dfrac{7}{4}+\dfrac{1}{2}+\dfrac{3}{8}\\ =\left(\dfrac{2}{3}+\dfrac{1}{2}\right)+\left(\dfrac{7}{4}+\dfrac{3}{8}\right)=\dfrac{7}{6}+\dfrac{17}{8}=\dfrac{79}{24}\)

Nguyễn Lê Phước Thịnh
6 tháng 10 2021 lúc 21:33

c: \(\dfrac{4}{5}-\dfrac{-2}{7}-\dfrac{-7}{10}\)

\(=\dfrac{56}{70}+\dfrac{20}{70}+\dfrac{49}{70}\)

\(=\dfrac{125}{70}=\dfrac{25}{14}\)

ĐOÀN THỊ MINH HIỀN
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Nguyễn Hoàng Minh
26 tháng 9 2021 lúc 21:12

\(b,\Rightarrow\dfrac{x}{2}-\dfrac{3x}{5}-\dfrac{13}{5}=-\dfrac{7}{5}-\dfrac{7x}{10}\\ \Rightarrow\dfrac{1}{2}x-\dfrac{3}{5}x+\dfrac{7}{10}x=\dfrac{6}{5}\\ \Rightarrow\dfrac{3}{5}x=\dfrac{6}{5}\Rightarrow x=2\\ c,\Rightarrow\dfrac{2x-3}{3}-\dfrac{5-3x}{6}=-\dfrac{1}{3}+\dfrac{3}{2}=\dfrac{7}{6}\\ \Rightarrow\dfrac{4x-6-5+3x}{6}=\dfrac{7}{6}\\ \Rightarrow7x-11=7\Rightarrow x=\dfrac{18}{7}\\ d,\Rightarrow\dfrac{2}{3x}+\dfrac{7}{x}=\dfrac{4}{5}+2+\dfrac{3}{12}=\dfrac{61}{20}\\ \Rightarrow\dfrac{23}{3x}=\dfrac{61}{20}\\ \Rightarrow183x=460\\ \Rightarrow x=\dfrac{460}{183}\\ e,\Rightarrow2\left(x-1\right)-\left(x-1\right)^2=0\\ \Rightarrow\left(x-1\right)\left(2-x+1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=1\\x=3\end{matrix}\right.\)

Nguyễn Lê Phước Thịnh
26 tháng 9 2021 lúc 21:14

e: Ta có: \(\left(x-1\right)^2=2\left(x-1\right)\)

\(\Leftrightarrow\left(x-1\right)\left(x-3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=3\end{matrix}\right.\)

ANH HOÀNG
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Lấp La Lấp Lánh
28 tháng 9 2021 lúc 12:54

a) \(\left|3x-\dfrac{1}{2}\right|+\left|\dfrac{1}{4}y+\dfrac{3}{5}\right|=0\)

Do \(\left|3x-\dfrac{1}{2}\right|,\left|\dfrac{1}{4}y+\dfrac{3}{5}\right|\ge0\forall x,y\)

\(\Rightarrow\left\{{}\begin{matrix}3x-\dfrac{1}{2}=0\\\dfrac{1}{4}y+\dfrac{3}{5}=0\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{1}{6}\\y=-\dfrac{12}{5}\end{matrix}\right.\)

b) \(\left|\dfrac{3}{2}x+\dfrac{1}{9}\right|+\left|\dfrac{5}{7}y-\dfrac{1}{2}\right|\le0\)

Do \(\left|\dfrac{3}{2}x+\dfrac{1}{9}\right|,\left|\dfrac{5}{7}y-\dfrac{1}{2}\right|\ge0\forall x,y\)

\(\Rightarrow\left\{{}\begin{matrix}\dfrac{3}{2}x+\dfrac{1}{9}=0\\\dfrac{5}{7}y-\dfrac{1}{2}=0\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x=-\dfrac{2}{27}\\y=\dfrac{7}{10}\end{matrix}\right.\)

Edogawa Conan
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Thầy Đức Anh
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Yen Nhi
21 tháng 6 2022 lúc 21:10

\(a)\left(\dfrac{1}{2}+1,5\right)x=\dfrac{1}{5}\)

\(\Rightarrow2x=\dfrac{1}{5}\)

\(\Rightarrow x=\dfrac{1}{10}\)

\(b)\left(-1\dfrac{3}{5}+x\right):\dfrac{12}{13}=2\dfrac{1}{6}\)

\(\Leftrightarrow-\dfrac{8}{5}+x=\dfrac{13}{6}.\dfrac{12}{13}\)

\(\Leftrightarrow-\dfrac{8}{5}+x=2\)

\(\Leftrightarrow x=\dfrac{18}{5}\)

\(c)\left(x:2\dfrac{1}{3}\right).\dfrac{1}{7}=-\dfrac{3}{8}\)

\(\Leftrightarrow x:\dfrac{7}{3}=-\dfrac{3}{8}:\dfrac{1}{7}\)

\(\Leftrightarrow x=-\dfrac{21}{8}.\dfrac{7}{3}\)

\(\Leftrightarrow x=-\dfrac{49}{8}\)

\(d)-\dfrac{4}{7}x+\dfrac{7}{5}=\dfrac{1}{8}:\left(-1\dfrac{2}{3}\right)\)

\(\Leftrightarrow-\dfrac{4}{7}x+\dfrac{7}{5}=-\dfrac{3}{40}\)

\(\Leftrightarrow-\dfrac{4}{7}x=-\dfrac{59}{40}\)

\(\Leftrightarrow x=\dfrac{413}{160}\)

 

Lac Lac
7 tháng 7 2022 lúc 16:16

a= 1/10

b= 18/5

c= -49/8

d= 413

 

Em Yeu Toan VN
8 tháng 7 2022 lúc 19:23

.

Kfkfj
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Nguyễn Lê Phước Thịnh
15 tháng 5 2022 lúc 19:23

a: (x+1/2)(2/3-2x)=0

=>x+1/2=0 hoặc 2/3-2x=0

=>x=-1/2 hoặc x=1/3

b: undefined

c: \(\Leftrightarrow x\cdot\left(\dfrac{13}{4}-\dfrac{7}{6}\right)=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{5}{12}+\dfrac{20}{12}=\dfrac{25}{12}\)

\(\Leftrightarrow x=\dfrac{25}{12}:\dfrac{39-14}{12}=\dfrac{25}{25}=1\)

Đinh Cẩm Tú
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Nguyễn Lê Phước Thịnh
31 tháng 1 2021 lúc 21:40

a) Ta có: \(\dfrac{x+4}{5}-x+4=\dfrac{x}{3}-\dfrac{x-2}{2}\)

\(\Leftrightarrow\dfrac{6\left(x+4\right)}{30}-\dfrac{30x}{30}+\dfrac{120}{30}=\dfrac{10x}{30}-\dfrac{15\left(x-2\right)}{30}\)

\(\Leftrightarrow6x+24-30x+120=10x-15x+30\)

\(\Leftrightarrow-24x+144=-5x+30\)

\(\Leftrightarrow-24x+5x=30-144\)

\(\Leftrightarrow-19x=-114\)

hay x=6

Vậy: S={6}

b) Ta có: \(\dfrac{4-5x}{6}=\dfrac{2\left(-x+1\right)}{2}\)

\(\Leftrightarrow2\cdot\left(4-5x\right)=12\left(-x+1\right)\)

\(\Leftrightarrow2-10x=-12x+12\)

\(\Leftrightarrow2-10x+12x-12=0\)

\(\Leftrightarrow2x-10=0\)

\(\Leftrightarrow2x=10\)

hay x=5

Vậy: S={5}

c) Ta có: \(\dfrac{-\left(x-3\right)}{2}-2=\dfrac{5\left(x+2\right)}{4}\)

\(\Leftrightarrow\dfrac{2\left(3-x\right)}{4}-\dfrac{8}{4}=\dfrac{5\left(x+2\right)}{4}\)

\(\Leftrightarrow6-2x-8=5x+10\)

\(\Leftrightarrow-2x+2-5x-10=0\)

\(\Leftrightarrow-7x-8=0\)

\(\Leftrightarrow-7x=8\)

hay \(x=-\dfrac{8}{7}\)

Vậy: \(S=\left\{-\dfrac{8}{7}\right\}\)

d) Ta có: \(\dfrac{7-3x}{2}-\dfrac{5+x}{5}=1\)

\(\Leftrightarrow\dfrac{5\left(7-3x\right)}{10}-\dfrac{2\left(x+5\right)}{10}=\dfrac{10}{10}\)

\(\Leftrightarrow35-15x-2x-10-10=0\)

\(\Leftrightarrow-17x+15=0\)

\(\Leftrightarrow-17x=-15\)

hay \(x=\dfrac{15}{17}\)

Vậy: \(S=\left\{\dfrac{15}{17}\right\}\)

Ngô Đức Kiên
1 tháng 2 2021 lúc 10:01

a) Ta có: ⇔6(x+4)30−30x30+12030=10x30−15(x−2)30⇔6(x+4)30−30x30+12030=10x30−15(x−2)30

⇔6x+24−30x+120=10x−15x+30⇔6x+24−30x+120=10x−15x+30

⇔−24x+144=−5x+30⇔−24x+144=−5x+30

⇔−24x+5x=30−144⇔−24x+5x=30−144

⇔−19x=−114⇔−19x=−114

hay x=6

Vậy: S={6}

b) Ta có: −(x−3)2−2=5(x+2)4−(x−3)2−2=5(x+2)4

x=−87x=−87

Vậy: 7−3x2−5+x5=17−3x2−5+x5=1

x=1517x=1517

Vậy: x+45−x+4=x3−x−22x+45−x+4=x3−x−22

4−5x6=2(−x+1)24−5x6=2(−x+1)2

⇔2⋅(4−5x)=12(−x+1)⇔2⋅(4−5x)=12(−x+1)

⇔2−10x=−12x+12⇔2−10x=−12x+12

⇔2−10x+12x−12=0⇔2−10x+12x−12=0

⇔2x−10=0⇔2x−10=0

⇔2x=10⇔2x=10

hay x=5

Vậy: S={5}

c) Ta có: ⇔2(3−x)4−84=5(x+2)4⇔2(3−x)4−84=5(x+2)4

⇔6−2x−8=5x+10⇔6−2x−8=5x+10

⇔−2x+2−5x−10=0⇔−2x+2−5x−10=0

⇔−7x−8=0⇔−7x−8=0

⇔−7x=8⇔−7x=8

hay S={−87}S={−87}

d) Ta có: ⇔5(7−3x)10−2(x+5)10=1010⇔5(7−3x)10−2(x+5)10=1010

⇔35−15x−2x−10−10=0⇔35−15x−2x−10−10=0

⇔−17x+15=0⇔−17x+15=0

⇔−17x=−15⇔−17x=−15

hay S={1517}