Bài 46:

11: Ta có: \(-4\left|x-2\right|=-8\)

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

\(\Leftrightarrow\left[{}\begin{matrix}x-2=2\\x-2=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=0\end{matrix}\right.\)

Vậy: x∈{0;4}

12: Ta có: \(5\left|x+2\right|=-10\cdot\left(-2\right)\)

\(\Leftrightarrow5\left|x+2\right|=20\)

\(\Leftrightarrow\left|x+2\right|=4\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=4\\x+2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-6\end{matrix}\right.\)

Vậy: x∈{-6;2}

13: Ta có: \(6\left|x-2\right|=18:\left(-3\right)\)

\(\Leftrightarrow6\left|x-2\right|=-6\)(1)

Ta có: \(\left|x-2\right|\ge0\forall x\)

\(\Rightarrow6\left|x-2\right|\ge0\forall x\)(2)

Ta có: -6<0(3)

Từ (1), (2) và (3) suy ra x∈∅

Vậy: x∈∅

14: Ta có:\(-7\left|x+4\right|=21:\left(-3\right)\)

\(\Leftrightarrow-7\left|x+4\right|=-7\)

\(\Leftrightarrow\left|x+4\right|=1\)

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

Vậy: x∈{-5;-3}

15: Ta có: \(4\left|x+1\right|=8\left(-2\right)-8\left(-5\right)\)

\(\Leftrightarrow4\left|x+1\right|=-16-\left(-40\right)\)

\(\Leftrightarrow4\left|x+1\right|=24\)

\(\Leftrightarrow\left|x+1\right|=6\)

\(\Leftrightarrow\left[{}\begin{matrix}x+1=6\\x+1=-6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-7\end{matrix}\right.\)

Vậy: x∈{-7;5}

16: Ta có: \(3\left|x+5\right|=-9\)(4)

Ta có: |x+5|≥0∀x

⇒3|x+5|≥0∀x(5)

Ta có: -9<0(6)

Từ (4), (5) và (6) suy ra x∈∅

Vậy: x∈∅

17: Ta có: \(-8\left|x-3\right|=24-16:2\)

\(\Leftrightarrow-8\left|x-3\right|=16\)

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

mà |x-3|≥0>-2∀x

nên x∈∅

Vậy: x∈∅

18: Ta có: \(-3\left|x+6\right|=6\cdot2-9\)

\(\Leftrightarrow-3\left|x+6\right|=3\)

\(\Leftrightarrow\left|x+6\right|=-1\)

mà |x+6|≥0>-1∀x

nên x∈∅

Vậy: x∈∅

19: Ta có: \(5-\left|x+7\right|=4\)

\(\Leftrightarrow\left|x+7\right|=1\)

\(\Leftrightarrow\left[{}\begin{matrix}x+7=-1\\x+7=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-8\\x=-6\end{matrix}\right.\)

Vậy: x∈{-8;-6}

20: Ta có: \(12-\left|x+8\right|=10\)

\(\Leftrightarrow\left|x+8\right|=2\)

\(\Leftrightarrow\left[{}\begin{matrix}x+8=2\\x+8=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-6\\x=-10\end{matrix}\right.\)

Vậy: x∈{-10;-6}

a)15/8+3/4-5/12

=45+18-10/24

=53/24

b)11/24.12/33+5/6

=11.12/12.2.11.3+5/6

=1/6+5/6

=6/6=1

c)15/8+7/24:5/8

=15/8+7/24.8/5

=15/8+7.8/3.8.5

=15/8+7/15

=đề sai, nếu đúng thì như này

=8/15+7/15

=15/15=1

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`x/8 = 3/4 +(-5/8)`

`=>x/8 = 6/8 +(-5/8)`

`=>x/8 = 1/8`

`=>x=1`

`-----`

`x/12 =3/4 +(-2/3)`

`=>x/12 = 9/12 + (-8/12)`

`=> x/12=1/12`

`=>x=1`

`----`

`1+11/13=24/x`

`=> 13/13 +11/13=24/x`

`=> 24/13 =24/x`

`=>x=13`

`----`

`x/6 -3/4=1/12`

`=>x/6 = 1/12 +3/4`

`=>x/6 = 1/12 + 9/12`

`=>x/6 = 10/12`

`=>x/6= 5/6`

`=>x=5`

\(a)\)

\(\dfrac{x}{8}=\dfrac{3}{4}+\dfrac{-5}{8}\)

\(\Rightarrow\dfrac{x}{8}=\dfrac{1}{8}\)

\(\Rightarrow x.8=1.8\)

\(\Rightarrow x.8=8\)

\(\Rightarrow x=8:8\)

\(\Rightarrow x=1\)

\(b)\)

\(\dfrac{x}{12}=\dfrac{3}{4}+\dfrac{-2}{3}\)

\(\Rightarrow\dfrac{x}{12}=\dfrac{1}{12}\)

\(\Rightarrow x.12=1.12\)

\(\Rightarrow x.12=12\)

\(\Rightarrow x=12:12\)

\(\Rightarrow x=1\)

\(c)\)

\(1+\dfrac{11}{13}=\dfrac{24}{x}\)

\(\Rightarrow\dfrac{24}{13}=\dfrac{24}{x}\)

\(\Rightarrow x.24=24.13\)

\(\Rightarrow x.24=312\)

\(\Rightarrow x=312:24\)

\(\Rightarrow x=13\)

\(d)\)

\(\dfrac{x}{6}-\dfrac{3}{4}=\dfrac{1}{12}\)

\(\Rightarrow\dfrac{x}{6}=\dfrac{1}{12}+\dfrac{3}{4}\)

\(\Rightarrow\dfrac{x}{6}=\dfrac{5}{6}\)

\(\Rightarrow x.6=5.6\)

\(\Rightarrow x.6=30\)

\(\Rightarrow x=30:6\)

\(\Rightarrow x=5\)

a= -1/7

b -50/21

c   1/8

d 19/56

e-13/24

f -89/312

thu gọn 7^3*7^5

Oh no nhiều kí tự đặc biệt quá

dễ quá mình ko làm  đc 

mình giải từng bài nhá

hả đơn giản

4.x=16

nhiều quá :((

\(a,2\left(x-5\right)-3\left(x+7\right)=14\)

\(2x-10-3x-21=14\)

\(-x-31=14\)

\(-x=45\)

\(x=45\)

\(b,5\left(x-6\right)-2\left(x+3\right)=12\)

\(5x-30-2x-6=12\)

\(3x-36==12\)

\(3x=48\)

\(x=16\)

\(c,3\left(x-4\right)-\left(8-x\right)=12\)

\(3x-12-8+x=0\)

\(4x-20=0\)

\(4x=20\)

\(x=5\)

Cố nốt nha bn ! 

cảm ơn, bn nha:)))

mà hình như bạn TOP 3 trả lời câu hỏi pải ko nhỉ???

d, \(-7\left(3x-5\right)+2\left(7x-14\right)=28\)

\(\Leftrightarrow-21x+35+14x-28=28\Leftrightarrow-7x=21\Leftrightarrow x=-3\)

e, \(5\left(3-2x\right)+5\left(x-4\right)=6-4x\)

\(\Leftrightarrow15-6x+5x-20=6-4x\Leftrightarrow-5-x=6-4x\)

\(\Leftrightarrow-11+3x=0\Leftrightarrow x=\frac{11}{3}\)

f, \(-5\left(2-x\right)+4\left(x-3\right)=10x-15\)

\(\Leftrightarrow-10+5x+4x-12=10x-15\Leftrightarrow-22+9x=10x-15\)

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

Câu 1: 

a: \(\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{2}{5}=\dfrac{20-15+24}{60}=\dfrac{29}{60}\)

b: \(\dfrac{1}{3}-\dfrac{4}{5}+\dfrac{4}{3}=\dfrac{5}{3}-\dfrac{4}{5}=\dfrac{25-12}{15}=\dfrac{13}{15}\)

c: \(=\dfrac{1}{2}+\dfrac{1}{6}-\dfrac{1}{4}+\dfrac{1}{5}\)

\(=\dfrac{30}{60}+\dfrac{10}{60}-\dfrac{15}{60}+\dfrac{12}{60}\)

=37/60

a)\(x-\frac{1}{4}=\frac{5}{8}\)

\(x=\frac{5}{8}+\frac{1}{4}\)

\(x=\frac{7}{8}\)

b)\(\frac{x}{12}=\frac{-1}{24}-\frac{1}{8}\)

\(\frac{x}{12}=\frac{-1}{24}+\frac{-1}{8}\)

\(\frac{x}{12}=\frac{-1}{6}\)

\(x=\frac{-1}{6}\times12\)

\(x=-2\)

a)x-1/4=5/8

=>x=5/8+1/4

x=7/8

b) x/12=-1/24-1/8

=>x/12=-1/6

=>x=-2

c).......... Tự làm

c)

\(\left(\frac{1}{4}-\frac{3}{10}x\right)\times\frac{1}{3}=\frac{-51}{6}+\frac{1}{4}\)

\(\left(\frac{1}{4}-\frac{3}{10}x\right)\times\frac{1}{3}=\frac{-33}{4}\)

\(\frac{1}{4}-\frac{3}{10}x=\frac{-33}{4}\div\frac{1}{3}\)

\(\frac{1}{4}-\frac{3}{10}x=\frac{-33}{4}\times3\)

\(\frac{1}{4}-\frac{3}{10}x=\frac{-99}{4}\)

\(\frac{3}{10}x=\frac{1}{4}-\left(\frac{-99}{4}\right)\)

\(\frac{3}{10}x=\frac{1}{4}+\frac{99}{4}\)

\(\frac{3}{10}x=25\)

\(x=\frac{250}{3}\)