Bài làm

(15 + x) - (x - 27) =  x - 24

15 + x - x + 27 = x -24

(15 + 27) + ( x - x) = x - 24

x - 24 = 42

       x = 42 - 24

       x = 18 

Vậy x = 18

Học & Tốt

\(\left(27-x\right)+\left(15+x\right)=x-24\)

\(27-x+15+x=x-24\)

\(-x+x-x=-24-15-27\)

\(-x=-66\)

\(\Rightarrow x=-66\)

\(\left(27-x\right)+\left(15+x\right)=x-24\)

\(27-x+15+x=x-24\)

\(32-x+24=0\)

\(56-x=0\)

\(x=56\)

(27 - x) + (15 + x) = x - 24

27 - x + 15 + x = x - 24

27 + 15 + 24 = x + x - x

66 = x

Vậy x = 66

Chúc bạn học tốt !

(27-x)+(15+x) = x-24 

27-x+15+x = x-24

27-15-x+x = x-24

12 = x-24

x-24 = 12

x =  36

Phương pháp giải:

- Muốn tìm số bị trừ ta lấy hiệu cộng với số trừ.

- Muốn tìm một số hạng ta lấy tổng trừ đi số hạng kia.

Lời giải chi tiết:

a) x − 27 = 15

    x = 15 + 27

    x = 42

b) x + 38 = 83

    x = 83 − 38

    x = 45

c) 24 + x = 73

    x = 73 − 24

    x = 49

Phân tích vế trái \(\left(27-x\right)+\left(15+x\right)=27+15-x+x=42\)

\(\Rightarrow x-24=42\)

\(x=66\)

\(\left(27-x\right)+\left(15+x\right)=x-24\)

\(\Leftrightarrow27-x+15+x-x+24=0\)

\(\Leftrightarrow66-x=0\)

\(\Leftrightarrow x=66\)

Vậy \(x=66\)

( 27 - x ) + ( 15 + x ) = x - 24

<=> 27 -x + 15 + x = x - 24

<=> 42 =x - 24

<=> x = 18

a)\(x-5=-1\)

⇔\(x=4\)

b)\(x+30=-4\)

⇔\(x=-34\)

c)\(x-\left(-24\right)=3\)

⇔\(x+24=3\)

⇔\(x=-21\)

e)\(\left(x+5\right)+\left(x-9\right)=x+2\)

⇔\(x+5+x-9-x-2=0\)

⇔\(x-6=0\)

⇔\(x=6\)

f)\(\left(27-x\right)+\left(15+x\right)=x-24\)

⇔\(27-x+15+x-x+24=0\)

⇔\(66-x=0\)

⇔\(x=66\)

\(a.x-5=-1\)                      \(b.x+30=-4\)

\(x=\left(-1\right)+5\)                        \(x=\left(-4\right)-30\)

\(x=4\)                                    \(x=-34\)

\(c.x-\left(-24\right)=3\)                    \(e.\left(x+5\right)+\left(x-9\right)=x+2\)

\(x=3+\left(-24\right)\)                         \(x+5+x-9=x+2\)

\(x=-21\)                                  \(2x-4=x+2\)

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

                                                 \(x=6\)

\(f.\left(27-x\right)+\left(15+x\right)=x-24\)

\(27-x+15+x=x-24\)

\(27+15=x-24\)

\(42=x-24\)

\(x=24+42\)

\(x=66\)

(27-x)+(15+x)=x-24

27-x+15+x=x-24

27+15+24=x+x-x

42+24=2x-x

66=x

vậy x=66

27-x + 15 + x = x - 24

=> 42 = x - 24

=> x = 24 + 42 = 66

( 27 - x ) + ( 15 + x ) = x - 24

<=> 27 - x + 15 + x = x - 24

<=> 42 = x - 24

<=> x = 66

e) (x+5) + (x-9) = x+2

     x+5 + x -9    = x+2

     2x + 5 - 9     = x+2

            2x - 4    = x +2

               3x      = 2 +4

                3x     =6

                   x    = 2

f) (27-x) + ( 15+x) = x-24

   27-x + 15 +x      = x-24

   27 + 15 - (x - x) = x - 24

                     42   = x-24

                       x = 24 + 42

                        x = 66

`@` `\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