1: x=3/4-1/2=3/4-2/4=1/4

2: x-1/5=2/11

=>x=2/11+1/5=21/55

3: x-5/6=16/42-8/56

=>x-5/6=8/21-4/28=5/21

=>x=5/21+5/6=15/14

4: x/5=5/6-19/30

=>x/5=25/30-19/30=6/30=1/5

=>x=1

5: =>|x|=1/3+1/4=7/12

=>x=7/12 hoặc x=-7/12

6: x=-1/2+3/4

=>x=3/4-1/2=1/4

11: x-(-6/12)=9/48

=>x+1/2=3/16

=>x=3/16-1/2=-5/16

1)x= 1/4

2)x= 2/11+ 1/5

   x= 21/55

3)x - 5/6 = 5/21

   x         = 5/21+5/6

   x         = 15/14

4)x/5 = 5/6 + -19/30

   x:5 = 1/5

   x    = 1/5.5

   x    = 1

5) |x| - 1/4 = 6/18

    |x|           = 6/18 - 1/4

    |x|            =7/12

⇒x= 7/12 hoặc -7/12

6)x = -1/2 +3/4

   x= 1/4

7) x/15 = 3/5 + -2/3

   x:15  = -1/15

  x        = -1/15. 15

  x        = -1

8)11/8 + 13/6 = 85/x  

       85/24      = 85/x

  ⇒      x           = 24

9) x - 7/8 = 13/12

   x          = 13/12 + 7/8

   x          = 47/24

10)x - -6/15 = 4/27  

     x            = 4/27 + (-6/15)

    x             = -34/135

11) -(-6/12)+x = 9/48

                    x= 9/48 - 6/12

                    x = -5/16

12) x - 4/6 = 5/25 + -7/15

      x -4/6  =  -4/15

     x           = -4/15 + 4/6

    x             = 2/5

a,\(2,5.16,27.4+7,3=16,27.10+7,3=162,7+7,3=170\)

b,\(8.6.10+4.25.12+3.16.31+2.34.24=48.10+48.25+48.31+48.34\)

\(=48.\left(10+25+31+34\right)=48.100=4800\)

c,\(78.31+78.24+78.17+22.72=78\left(31+24+17\right)+22.72=78.72+22.72\)

\(=72.\left(78+22\right)=72.100=7200\)

d,\(102.67-34.51=102.67-17.102=102.\left(67-17\right)=102.50=5100\)

đéo hiểu thì cút nhé đéo ai khiến m trả lời cả . ngu thì nói ngu đi đừng bày đặt t ghét nhất là cái loại như m đấy ạ 

Bài 2 

a, \(1-\left(12,5+x-4,25\right):21,75=0\)

\(=>21,75-12,5-x+4,25=0\)

\(=>13,5-x=0=>x=13,5\)

b,\(x.101-x+72.99+72=21050\)

\(=>100x+72.100=21050\)

\(=>100\left(x+72\right)=21050\)

\(=>x+72=210,5\)\(=>x=138,5\)

c,\(151-2\left(x-6\right)=2227:17\)

\(=>151-2\left(x-6\right)=131\)

\(=>2\left(x-6\right)=20\)

\(=>2x=32=>x=16\)

d,\(\left(x+4\right)+\left(x+6\right)+\left(x+8\right)+...+\left(x+26\right)=210\)\(=>12x+\left(4+6+8+...+26\right)=210\)

\(=>12x+180=210=>12x=30\)

\(=>x=\frac{30}{12}=\frac{15}{6}=\frac{5}{2}\)

a)   x + 118 = 218

x = 218 – 118

x = 100

b)   18 – x = -17

X = 18 – (-17)

X = 35

c)    (-18) – x = -17

X = (-18) – (-17)

X = -1

d)124 + (118 – x) = 217

118 – x = 93

X = 118 – 93

X = 25

e) (3x – 6).3 = 3⁴

(3x – 6).3 = 81

3x – 6 = 27

3x = 33

ð X = 11

g) 23.(42 – x) = 46

42 – x = 2

ð X = 40

h) 84 – (3x + 8) = 34

3x + 8 = 84 – 34

3x + 8 = 50

3x = 50 – 8

3x = 42

X = 42 : 3

ð X = 14

i)               3.(2x + 1) – 19 = 14

3.(2x + 1) = 14 + 19

3.(2x + 1) = 33

2x + 1 = 33 : 3

2x + 1 = 11

2x = 11 – 1

2x = 10

X = 10 : 2

ð X = 5

k) 6x – 302 = 2³.5

6x – 302 = 40

6x = 40 + 302

6x = 342

X = 342 : 6

ð X = 57

m) (x – 1)² = 81

(x – 1)² = 9²

ð X – 1 = 9

ð X = 9 + 1

ð X = 10

n) 2^x+1 – 5 = 27

2^x+1 = 27 + 5

2^x+1 = 32

2^x+1 = 2⁵

ð X = 4

a) \(x+118=218\)

    \(x=218-118\)

    \(x=100\) 

b)\(18-x=-17\)

   \(-x=-18-17\)

    \(-x=-35\)

     \(x=35\)

c)\(\left(-18\right)-x=-17\)

     \(-x=18-17\)

     \(-x=1\)

      \(x=-1\)

d)\(124+\left(118-x\right)=217\)

    \(118-x=217-124\)

     \(118-x=93\)

     \(x=25\)

e) \(\left(3x-6\right).3=3^4\)

     \(3x-6=3^3\)

     \(3x-6=27\)

     \(x=11\)

g)\(23.\left(42-x\right)=46\)

    \(42-x=2\)

     \(x=40\)

h) \(84-\left(3x+8\right)=34\)

    \(3x+8=50\)

     \(x=14\)

 i)  \(3\left(2x+1\right)-19=14\)

      \(3\left(2x+1\right)=33\)

       \(2x+1=11\)  

        \(x=5\)

k) \(6x-302=2^3.5\)

    \(6x-302=8.5\)

    \(x=57\)

m) \(\left(x-1\right)^2=81\)

      \(\left(x-1\right)^2=9^2\)

       \(x-1=9\)

       \(x=10\)

n) \(2^{x+1}-5=27\)

    \(2^{x+1}=32\)

    \(2^{x+1}=2^5\)

   \(x+1=5\)  

     \(x=4\)

m) \(2^x+2^{x+1}+2^{x+2}=56\)

    \(2^x.1+2^x.2+2^x.2^2=56\)

    \(2^x\left(1+2+4\right)=56\)

     \(2^x=8\)

    \(2^x=2^3\)

     \(x=3\)

   \(2^x=8\)

1. \(x-8+32=68\)

\(x-8=68-32\)

\(x-8=36\)

\(x=36+8\)

\(x=44\)

_____

2. \(x+8+32=68\)

\(x+8=68-32\)

\(x+8=36\)

\(x=36-8\)

\(x=28\)

_____

3. \(98-x+34=43\)

\(98-x=43-34\)

\(98-x=9\)

\(x=98-9\)

\(x=89\)

_____

4. \(98+x-34=43\)

\(98+x=43+34\)

\(98+x=77\)

\(x=77-98\)

\(x=-21\)

_____

5. \(x:5:4=800\)

\(x:5=800.4\)

\(x:5=3200\)

\(x=3200.5\)

\(x=16000\)

_____

6. \(18+x=384:8\)

\(18+x=48\)

\(x=48-18\)

\(x=30\)

_____

7. \(\left(84,6-2\times x\right):3,02=5,1\)

\(84,6-2.x=5,1.3,02\)

\(84,6-2.x=15,402\)

\(2.x=84,6-15,402\)

\(2.x=69,198\)

\(x=69,198:2\)

\(x=34,599\)

_____

8. \(x\times5=120:6\)

\(x.5=20\)

\(x=20:5\)

\(x=4\)

_____

9. \(\left(15\times24-x\right):0,25=100:0,25\)

\(\left(15.24-x\right):0,25=400\)

\(15.24-x=400.0,25\)

\(15.24-x=100\)

\(360-x=100\)

\(x=360-100\)

\(x=260\)

1,x-8+32=68

=>x-8=68-32=36

=>x=36+8=42

2,x+8+32=68

=>x+8=68-32=36

=>x=36-8=28

3,98-x+34=43

=>98-x=43-34=9

=>x=98-9=89

4,98+x-34=43

=>98+x=43+34=77

=>x=77-98=-21

5,x:5:4=800

=>x:20=800

=>x=800x20=16000

6,18+x=384:8=48

=>x=48-18=30

7,(84,6-2x):3,02=5,1

=>84,6-2x=5,1x3,02=15,402

=>2x=84,6-15,402=69,198

=>x=69,198:2=34,599

8,5x=120:6=20

=>x=20:5=4

9,(15x24-x):0,25=100:0,25=400

=>360-x=400x0,25=100

=>x=360-100=260.

1. \(...\Rightarrow x+24=68\Rightarrow x=68-24=44\)

2. \(...\Rightarrow x+40=68\Rightarrow x=68-40=28\)

3. \(...\Rightarrow3^{2\left(8+x\right)}=9=3^2\Rightarrow2\left(8+x\right)=2\Rightarrow8+x=1\Rightarrow x=-7\)

4. \(...\Rightarrow3^{2\left(8+x\right)}=77\) (bạn xem lại đề)

5. \(...\Rightarrow x:5=800.4\Rightarrow x:5=3200\Rightarrow x=3200.5=16000\)

6. \(...\Rightarrow18+x=48\Rightarrow x=48-18=30\)

7. \(...\Rightarrow84,6-2x=5,1.3,02=15,402\Rightarrow2x=84,6-15,402\Rightarrow2x=69,198\Rightarrow x=34,599\)

8. \(...\Rightarrow5.x=20\Rightarrow x=20:5=4\)

9. \(\left(360-x\right):0,25=400\Rightarrow360-x=400.0,25=100\Rightarrow x=400-100=300\)

a) \(\frac{18}{45}-\frac{4}{12}-\frac{6}{9}-\frac{21}{35}=\frac{2}{5}-\frac{1}{3}-\frac{2}{3}-\frac{3}{5}\)

\(=\left(\frac{2}{5}-\frac{3}{5}\right)-\left(\frac{1}{3}+\frac{2}{3}\right)\)

\(=\frac{-1}{3}-1\)

\(=\frac{-4}{3}\)

b) \(\frac{4}{3}+\frac{3}{5}+\frac{7}{3}+\frac{2}{5}+\frac{1}{3}=\left(\frac{4}{3}+\frac{7}{3}+\frac{1}{3}\right)+\left(\frac{3}{5}+\frac{2}{5}\right)\)

\(=4+1=5\)

c) \(\frac{1}{3}.\frac{4}{5}.\frac{1}{3}.\frac{6}{5}=\frac{8}{75}\)

d) \(\frac{6}{7}.\frac{8}{13}+\frac{6}{7}.\frac{9}{13}-\frac{3}{13}.\frac{6}{7}\)

\(=\frac{6}{7}.\left(\frac{8}{13}+\frac{9}{13}-\frac{3}{13}\right)\)

\(=\frac{6}{7}.\frac{14}{13}\)

\(=\frac{12}{13}\)

1) 3/4 : x/6 = 75/100

           x/6 = 3/4 : 75/100

           x/6 = 1

              x = 1*6

              x = 6

Câu 6: Bạn xem ở đây: http://olm.vn/hoi-dap/question/615090.html

PT2 thiếu đề hay sao í

1.\(\frac{3}{4}:\frac{x}{6}=\frac{75}{100}\) \(\Leftrightarrow\frac{3}{4}.6.\frac{1}{x}=\frac{3}{4}\)

                                \(\Leftrightarrow\frac{6}{x}=1\)

                                 \(\Leftrightarrow x=\frac{1}{6}\)

cậu giải đi. cau 2 ko giải đâu

dài thế

dai the giai bao gio xong chac mua quyt nam sau moi giai xong

Giả sử các bài của bạn x ϵ N (vì đề bài của bạn không nói)

1) Ư(42)={1;2;3;6;7;14;21;42}

    B(6)={0;6;12;18...}

2) A={xϵB(4)/x<26}={0;4;12;16;20;24}

    B={xϵƯ(36)/6<x<18}={6;9;12}

3) a) x⋮4 và x<10

⇒ x ϵ {0;4;8}

    b) 96⋮x và x>16

⇒ x ϵ {24;32;48;96}

c) 8 ⋮ (x+1)

⇒ (x+1) là Ư(8)

⇒ (x+1) ϵ {1;2;4;8}

⇒ x ϵ {0;1;3;7}