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

\(\frac{-8}{40}\le\frac{5x}{40}\le\frac{10}{40}\)

\(\Rightarrow-8\le5x\le10\)

\(\Rightarrow x\in\left\{-5;0;5;10\right\}\)

5.x = - 5

x = -5 ÷ 5 = -1

5.x = 0

=> x = 0

5.x = 5

=> x = 1

5.x = 10

=> x = 2

Vậy, \(x\in\left\{-1;0;1;2\right\}\)

Câu b) mình không biết làm, bạn thông cảm nha!!!

Cbht

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

<=> \(-\frac{8}{40}\le\frac{5x}{40}\le\frac{10}{40}\)

<=> -8 \(\le\)5x \(\le\)10

<=> x + 5 \(\in\){\(\pm\)8;\(\pm\)7; \(\pm\)6;\(\pm\)5;\(\pm\)4;\(\pm\)3;\(\pm\)2; \(\pm\)1; 0; 9;10}

<=> x \(\in\left\{3;-13;2;-12;1;-11;0;-10;-1;-9;-2;-8;-3;-7;-4;-6;-5;4;5\right\}\)

b. \(\frac{x+46}{20}=x\frac{2}{5}\)

<=> 5x + 230 = 40x

<=> 35x = 230

<=> x = \(\frac{46}{7}\)

b) \(\frac{x+46}{20}=x\frac{2}{5}\)

\(\Leftrightarrow\frac{x+46}{20}=\frac{5x+2}{5}\)

\(\Leftrightarrow\frac{x+46}{20}=\frac{4\left(5x+2\right)}{20}\)

\(\Rightarrow x+46=4\left(5x+2\right)\)

\(\Leftrightarrow x+46=20x+8\)

\(\Leftrightarrow x-20x=8-46\)

\(\Leftrightarrow-19x=-38\)

\(\Leftrightarrow x=\left(-38\right):\left(-19\right)=2\)

Vậy x=2

\(x=2\)

tic cho mk nha

\(\frac{x+46}{20}=\frac{5x+2}{5}\)

=> (x+46).5=20.(5x+2)

=> 5x+230=100x+40

=> 5x-100x=40-230

=> -95x=-190

=> x=-190:(-95)

=> x=2

Tìm \(x\) câu a:

\(\frac13.x\) + \(\frac25.\left(x+1\right)\) = 0

\(\frac{5}{15}x\) + \(\frac{6}{15}x\) + \(\frac25\) = 0

\(\frac{11}{15}x\) = - \(\frac25\)

\(x=-\frac25:\frac{11}{15}\)

\(x\) = - \(\frac25\times\frac{15}{11}\)

\(x\) = - \(\frac{6}{11}\)

Vậy \(x=-\frac{6}{11}\)

Tìm \(x\) câu b:

\(x\) x 25% = 0,5

\(x\times0,25\) = 0,5

\(x=0,5:0,25\)

\(x=2\)

Vậy \(x=2\)

Câu 1a:

1/3x + 2/5(x + 1) = 0

1/3x + 2/5x + 2/5 = 0

1/3x + 2/5x = - 2/5

x(1/3 + 2/5) = -2/5

x.(5/15 + 6/15) = -2/5

x.11/15 = - 2/5

x = - 2/5 : 11/15

x = - 6/11

Vậy x = -6/11

Câu b:

x . 25%. x = 0,5

x.x = 0,5 : 25%

x^2 = 2

x = - \(\sqrt2\); x = \(\sqrt2\)

Vậy x ∈ {- \(\sqrt2\); \(\sqrt2\) )

Câu 1a:

1/3x + 2/5(x + 1) = 0

1/3x + 2/5x + 2/5 = 0

1/3x + 2/5x = - 2/5

x(1/3 + 2/5) = -2/5

x.(5/15 + 6/15) = -2/5

x.11/15 = - 2/5

x = - 2/5 : 11/15

x = - 6/11

Vậy x = -6/11

Câu b:

x . 25%. x = 0,5

x.x = 0,5 : 25%

x^2 = 2

x = - \(\sqrt2\); x = \(\sqrt2\)

Vậy x ∈ {- \(\sqrt2\); \(\sqrt2\) )

a: x/5=32/80

nên x/5=2/5

hay x=2

13/x=26/30

nên 13/x=13/15

hay x=15

-x/7=22/-77

=>x/7=2/7

hay x=2

b: x/9=28/36

=>x/9=7/9

hay x=7

-10/x=50/55

=>-10/x=10/11

hay x=-11

a)

1) x/5 = 32/80

\(x : 5 = 32 : 80\) \(x = 5 \cdot \frac{32}{80}\) \(x = 5 \cdot \frac{2}{5}\) \(x = 2\)

2) 13/x = 26/30

\(13 : x = 26 : 30\) \(13 \cdot 30 = x \cdot 26\) \(390 = 26 x\) \(x = 390 : 26\) \(x = 15\)

3) -x/7 = 22/(-77)

\(- x : 7 = 22 : \left(\right. - 77 \left.\right)\) \(- x = 7 \cdot \frac{22}{- 77}\) \(- x = 7 \cdot \left(\right. - \frac{2}{7} \left.\right)\) \(- x = - 2\) \(x = 2\)

b)

1) x/9 = 28/36

\(x : 9 = 28 : 36\) \(x = 9 \cdot \frac{28}{36}\) \(x = 9 \cdot \frac{7}{9}\) \(x = 7\)

2) -10/x = 50/55

\(- 10 : x = 50 : 55\) \(- 10 \cdot 55 = 50 x\) \(- 550 = 50 x\) \(x = - 550 : 50\) \(x = - 11\)

3) 23/(-x) = 46/50

\(23 : \left(\right. - x \left.\right) = 46 : 50\) \(23 \cdot 50 = 46 \left(\right. - x \left.\right)\) \(1150 = - 46 x\) \(x = 1150 : \left(\right. - 46 \left.\right)\) \(x = - 25\)

✅ Kết quả cuối cùng

a)

1. x = 2
2. x = 15
3. x = 2

b)

1. x = 7
2. x = -11
3. x = -25