1. Are there forty classrooms in Phong's school ?
2, Phuong is Nam's sister.

3. My father usually goes to work by car.

4. It is a small house.

5. The toystore is to the left of the bookstore.

1. Are there forty classrooms in Phong's school ?

2. Phuong is Nam' sister.

3. My father usually goes to work by car.

4. It is a small house.

5. The toystore is to the left of the bookstore.

1. Are there forty classroom in Phong's school?

2. Phuong is Nam's sister

3. My father go to work by car

4. It is a small house

5. The toystore is to the lerf of the bookstore

Học tốt!

+) Ta có: \(15-x+17=-\left(-6\right)+\left|-12\right|\)

        \(\Leftrightarrow-x+32=6+12\)

        \(\Leftrightarrow-x=18-32\)

        \(\Leftrightarrow x=14\)

Vậy......

+) Ta có: \(x+20=-\left(-23\right)\)

        \(\Leftrightarrow x+20=23\)

        \(\Leftrightarrow x=3\)

Vậy........

+) Ta có: \(-\left|-5\right|-\left(-x\right)+4=3-\left(-25\right)\)

       \(\Leftrightarrow-5+x+4=3+25\)

       \(\Leftrightarrow x=29\)

Vậy.....

Chúc e hok tốt và giữ lời hứa nhá ^_^

D={x|x=4k+3 với k thuộc N}      (4k+3 là chia 4 dư 3 đấy).

E={x|x=7k+2 với k thuộc N}

a) -(-x)+14=12

x+14=12

x=12-14

x=-2

Vậy x=-2

b) x+20=-(-23)

x+20=23

x=23-20

x=3

Vậy x=3

c) 15-x+17=-(-6)+|-12|

15-x+17=6+12

15-x+17=18

15-x=18-17

15-x=1

x=15-1

x=14

Vậy x=14

d) |x|=5

=>x thuộc {-5;5}

Vậy x thuộc {-5;5}

e) |x-3|=1

=>x-3 thuộc {1;-1}

vậy ta sẽ xét 2 TH:

TH1:x-3=1

x=1+3

x=4

TH2:x-3=-1

x=-1+3

x=2

Vậy x thuộc {2;4}

f) |x+2|=4

=>x+2 thuộc {4;-4}

vậy ta sẽ xét 2 TH:

TH1:x+2=4

x=4-2

x=2

TH2:x+2=-4

x=-4-2

x=6

Vậy x thuộc {2;6}

a, -(-x)+14=12

=>x+14=12

     x=12-14

    x=-2

b,x+20=-(-23)

  x+20=23

       x=23-20

      x=3

c,15-x+17=-(-6)+\(|-12|\)

   15-x+17=6+12

      32-x=18

         x=32-18

        x=14

d,\(|x|=5\)

\(TH1:x=5\)

\(TH2:x=-5\)

e,\(|x-3|=1\)

\(TH1:x-3=1\)

         \(x=1+3\)

         \(x=4\)

\(TH2:x-3=-1\)

            \(x=-1+3\)

            \(x=2\)

f,\(|x+2|=4\)

\(TH1:x+2=4\)

           \(x=4-2\)

           \(x=2\)

\(TH2:x+2=-4\)

           \(x=-4-2\)

          \(x=-6\)

#CHÚC_CẬU_HỌC_TỐT_NHÉ!

a, -(-x) + 14 = 12

     x             = 12 -14

     x             = -2

Vậy x  = -2

b, x + 20 = -(-23)

   x + 20  = 23

  x           = 23 - 20

  x           = 3

Vậy x  = 3

c, 15 - x + 17 = -(-6) + |-12|

    15 - x + 17 = 6 + 12

    15 - x + 17 = 18

    15 - x         = 18 - 17

    15 - x         = 1

          x           = 15 - 1

         x            = 14

Vậy x = 14.

d,  |x|=5

 \(\Rightarrow x=\mp5\)

Vậy \(x=\mp5\)

 e) |x-3|=1

\(\Rightarrow\orbr{\begin{cases}x-3=1\\x-3=-1\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=4\\x=2\end{cases}}\)

Vậy \(x\in\left\{4;2\right\}\)

f) |x+2|=4

\(\Rightarrow\orbr{\begin{cases}x+2=4\\x+2=-4\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=2\\x=-6\end{cases}}\)

Vậy \(x\in\left\{2;-6\right\}\)

Hok tốt !

a, 720 : ( x - 17 ) = 12

=> x - 17 = 720 : 12 = 60

=> x = 60 + 17 = 77

\(a,\text{ }720\text{ : }\left(x-17\right)=12\)

                 \(\left(x-17\right)=720\text{ : }12\)

                  \(\left(x-17\right)=60\)

                                    \(x=60+17\)

                                    \(x=77\)

b, 26 + 8x = 6x + 46

=> 8x - 6x = 46 - 26

=> 2x = 20

=>x = 20: 2 =10

`@` `\text {Ans}`

`\downarrow`

`c)`

`( 34 - 2x ) . ( 2x - 6 ) = 0`

`=>`\(\left[{}\begin{matrix}34-2x=0\\2x-6=0\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}2x=34\\2x=6\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=34\div2\\x=6\div2\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=17\\x=3\end{matrix}\right.\)

Vậy, `x \in {17; 3}`

`d)`

`( 2019 - x ) . ( 3x - 12 ) =0` `?`

`=>`\(\left[{}\begin{matrix}2019-x=0\\3x-12=0\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=2019-0\\3x=12\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=2019\\x=12\div3\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=2019\\x=4\end{matrix}\right.\)

Vậy, `x \in {2019; 4}`

`e) `

`57 . ( 9x - 27 ) = 0`

`=>`\(9x-27=0\div57\)

`=> 9x - 27 = 0`

`=> 9x = 27`

`=> x = 27 \div 9`

`=> x = 3`

Vậy, `x = 3`

`f)`

`25 + ( 15 - x ) = 30`

`=> 15 - x = 30 - 25`

`=> 15 - x = 5`

`=> x = 15 -5 `

`=> x = 10`

Vậy, `x = 10`

`g) `

`43 - ( 24 - x ) = 20`

`=> 24 - x = 43 - 20`

`=> 24 - x = 23`

`=> x = 24 - 23`

`=> x = 1`

Vậy, `x = 1`

`h) `

`2 . ( x - 5 ) - 17 = 25`

`=> 2 ( x - 5) = 25+17`

`=> 2 ( x - 5) = 42`

`=> x - 5 = 42 \div 2`

`=> x - 5 = 21`

`=> x = 21 + 5`

`=> x = 26`

Vậy, `x = 26`

`i)`

`3 . ( x + 7 ) - 15 = 27`

`=> 3(x + 7) = 27 + 15`

`=> 3(x + 7) = 42`

`=> x +7 = 42 \div 3`

`=> x + 7 = 14`

`=> x = 14 - 7`

`=> x = 7`

Vậy, `x = 7`

`j)`

`15 + 4 . ( x - 2 ) = 95`

`=> 4(x - 2) = 95 - 15`

`=> 4(x - 2) = 80`

`=> x - 2 = 80 \div 4`

`=> x - 2 = 20`

`=> x = 20 + 2`

`=> x = 22`

Vậy, `x = 22`

`k)`

`20 - ( x + 14 ) = 5`

`=> x + 14 = 20 - 5`

`=> x + 14 = 15`

`=> x = 15 - 14`

`=> x = 1`

Vậy, `x = 1`

`l) `

`14 + 3 . ( 5 - x ) = 27`

`=> 3(5 - x) = 27 - 14`

`=> 3(5 - x) = 13`

`=> 5 - x = 13 \div 3`

`=> 5 - x = 13/3`

`=> x = 5- 13/3`

`=> x = 2/3`

Vậy, `x = 2/3.`

`@` `\text {Kaizuu lv uuu}`

nhanh mik tick cho nha

2x+20=-22

=> 2x = -22 - 20

=> 2x = -42

=> x = -42 : 2

=> x = -21

Vậy x = -21

2x+20=-22

2x=-22-20

2x=-42

  x=-42:2

  x=-21

-(-30)-(-x)=13

30+x=13

      x=13-30

      x=-17

-(-x)+14=12

x+14=12

      x=12-14

      x=-2

x+20=-(-23)

x+20=23

      x=23-20

      x=3

15-x+17=-(-6)+|-12|

15+17+x=6+12

32+x=18

      x=18-32

      x=-14

-|-5|-(-x)+4=3-(-25)

-5+x+4=3+25

-5+4+x=28

-1x=28

   x=28:(-1)

   x=-28

cam on moi nguoi nhe

Hack nao

a) \(\dfrac{x}{5}+\dfrac{1}{2}=\dfrac{6}{10}\\ \dfrac{x}{5}+\dfrac{1}{2}=\dfrac{3}{5}\\ \dfrac{x}{5}=\dfrac{3}{5}-\dfrac{1}{2}\\ \dfrac{x}{5}=\dfrac{6}{10}-\dfrac{5}{10}\\ \dfrac{x}{5}=\dfrac{1}{10}\\ \dfrac{2x}{10}=\dfrac{1}{10}\\ \Rightarrow2x=1\\ x=1:2\\ x=0,5=\dfrac{1}{2}\)

b) \(x+\dfrac{3}{15}=\dfrac{1}{3}\\ x=\dfrac{1}{3}-\dfrac{3}{15}\\ x=\dfrac{5}{15}-\dfrac{3}{15}\\ x=\dfrac{2}{15}\)

c) \(x-\dfrac{12}{4}=\dfrac{1}{2}\\ x-3=\dfrac{1}{2}\\ x=\dfrac{1}{2}+3\\ x=\dfrac{1}{2}+\dfrac{6}{2}\\ x=\dfrac{7}{2}\)

d) \(\dfrac{1}{2}x+\dfrac{1}{2}=\dfrac{5}{2}\\ \dfrac{1}{2}x=\dfrac{5}{2}-\dfrac{1}{2}\\ \dfrac{1}{2}x=2\\ x=2:\dfrac{1}{2}\\ x=4\)

a. \(\dfrac{2x+5}{10}=\dfrac{6}{10}\Leftrightarrow2x=1\Leftrightarrow x=\dfrac{1}{2}\)

b. \(\dfrac{15x+3}{15}=\dfrac{5}{15}\Leftrightarrow15x=2\Leftrightarrow x=\dfrac{2}{15}\)

c. \(\dfrac{4x-12}{4}=\dfrac{2}{4}\Leftrightarrow4x=14\Leftrightarrow x=\dfrac{7}{2}\)

d. \(\dfrac{1+x}{2x}=\dfrac{5x}{2x}\Leftrightarrow-4x=-1\Leftrightarrow x=\dfrac{1}{4}\)

e. \(\dfrac{-4\left(2x-5\right)}{6\left(2x-5\right)}-\dfrac{2}{6\left(2x-5\right)}=\dfrac{9\left(2x-5\right)}{6\left(2x-5\right)}\)

\(\Leftrightarrow-8x+20-2=18x-45\)

\(\Leftrightarrow-26x=-63\Leftrightarrow x=\dfrac{63}{26}\)

f. \(\left(3x-1\right)\left(\dfrac{-1}{2x+5}\right)=0\)

\(\left[{}\begin{matrix}3x-1=0\Rightarrow3x=1\Rightarrow x=\dfrac{1}{3}\\\dfrac{-1}{2x+5}=0\Rightarrow2x+5=0\Rightarrow2x=-5\Rightarrow x=\dfrac{-5}{2}\end{matrix}\right.\)

g. \(\dfrac{6x}{12x}-\dfrac{8}{12x}=\dfrac{7x}{12x}\Leftrightarrow-x=8\Leftrightarrow x=-8\)

h. \(\dfrac{45}{60x}+\dfrac{12x}{6x}=\dfrac{10x}{60x}\Leftrightarrow2x=-45\Leftrightarrow x=\dfrac{-45}{2}\)