\(\left[195-\left(3x-27\right)\right]\cdot39=4212\)

\(\Rightarrow\left(195-3x+27\right)\cdot39=4212\)

\(\Rightarrow\left(-3x+222\right)\cdot39=4212\)

\(\Rightarrow-3x+222=\dfrac{4212}{39}\)

\(\Rightarrow-3x+222=108\)

\(\Rightarrow3x=222-108\)

\(\Rightarrow3x=114\)

\(\Rightarrow x=\dfrac{114}{3}\)

\(\Rightarrow x=38\)

=>[195-(3x-27)]=4212:39=108

=>3x-27=195-108=87

=>3x=27+87=114

=>x=38

\(a,91-5.\left(5+x\right)=61\\ \Rightarrow=5.\left(5+x\right)=30\\ \Rightarrow5+x=6\\ \Rightarrow x=1.\\ b,\left[195-\left(3x-27\right)\right].39=4212\\ \Rightarrow195-\left(3x-27\right)=108\\ \Rightarrow3x-27=87\\ \Rightarrow3x=114\\ \Rightarrow x=38.\)

\(91-5.\left(5+x\right)=61\)

\(\Rightarrow5.\left(5+x\right)=91-61\)

\(\Rightarrow5.\left(5+x\right)=30\)

\(\Rightarrow5+x=\dfrac{30}{5}=6\)

\(\Rightarrow x=6-5=1\)

\(\left[195-\left(3x-27\right)\right].39=4212\)

\(\Rightarrow195-3x+27=\dfrac{4212}{39}=108\)

\(\Rightarrow222-3x=108\)

\(\Rightarrow3x=222-108=114\)

\(\Rightarrow x=\dfrac{114}{3}=38\)

a,91-5(5+x)=61

=>25+5x=91-61=30

=>5x=30-25=5

=>x=1

b,\([\left(x+34\right)-50]\)x2=56

=>(x+34)-50=56:2=28

=>x+34=28+50=78

=>x=78-34=44.

c,1045-\([2015-\left(3x-24\right)]\)=5

=>2015-(3x-24)=1045-5=1040

=>3x-24=2015-1040=975

=>3x=975+24=999

=>x=999:3=333

d,\([195-\left(3x-27\right)]\)x39=4212

=>195-(3x-27)=4212:39=108

=>3x-27=195-108=87

=>3x=87+27=117

=>x=39

e,30-3(x-2)=18

=>30-3x+6=18

=>30-3x=18-6=12

=>3x=30-12=18

=>x=18:3=6

a) \(...\Rightarrow5\left(5+x\right)=91-61=30\)

\(\Rightarrow\left(5+x\right)=30:5=6\Rightarrow x=6-5=1\)

b) \(...\Rightarrow\left(x+34\right)-50=56:2=28\)

\(\Rightarrow\left(x+34\right)=28+50=78\Rightarrow x=78-34=44\)

c) \(...\Rightarrow2015-\left(3x-24\right)=1045-5=1040\)

\(\Rightarrow\left(3x-24\right)=2015-1040=975\)

\(\Rightarrow3x=975+24=999\Rightarrow x=999:3=333\)

d) \(...\Rightarrow195-\left(3x-27\right)=4212:39=108\)

\(\Rightarrow\left(3x-27\right)=195-108=87\)

\(\Rightarrow3x=87+27=114\Rightarrow x=114:3=38\)

e) \(...\Rightarrow3\left(x-2\right)=30-18=12\Rightarrow x-2=12:3=4\)

\(\Rightarrow x=4+2=6\)

\(\left[195-\left(3x-27\right)\right]\cdot39=4212\\ \Rightarrow195-\left(3x-27\right)=4212:39\\ \Rightarrow195-\left(3x-27\right)=108\\ \Rightarrow3x-27=195-108\\ \Rightarrow3x-27=87\\ \Rightarrow3x=87+27\\ \Rightarrow3x=114\\ \Rightarrow x=114:3\\ \Rightarrow x=38\)

\(\left[195-\left(3x-27\right)\right]\cdot39=4212\\ \Leftrightarrow195-\left(3x-27\right)=108\\ \Leftrightarrow3x-27=87\\ \Leftrightarrow3x=114\\ \Leftrightarrow x=38\)

Vậy x = 38.

[195-(15x-27).39=4212

195-(15x-27)=4212 : 39

195-(15x-27)=108

15x-27=195-108

15x-27=87

15x=87+27

15x=114

x=114:15

x=38/5

x=7,6

k đúng cho m nha bạn !

Đề thiếu bạn ạ.

\(1734:17=102x17:17=102x1=102\)

\(\left(x-7\right)\)\(2-26=13x17-13x7=13\left(17-7\right)=13x10=130\)

\(\left(x-7\right)2=130+26=156\)

\(x-7=156:2=78\)

\(x=78+7=85\)

\(=>x=85\)

\(195-\left(15x+27\right)=4212:39=108\)

\(15x+27=195-108=87\)

\(15x=87-27=60\)

\(x=60:15=4\)

\(=>x=4\)

- Tính nhẩm
1734 : 17 = 102

- Tìm x
(x - 7) .2 - 26 = 13.17 - 13.7
(x - 7) .2 - 26 = 13.(17 - 7)
(x - 7) .2 - 26 = 13. 10
(x - 7) .2 - 26 = 130
(x - 7) .2         = 130 + 26
(x - 7) .2         = 156
(x - 7)             = 156 : 2
(x - 7)             = 78
 x                    = 78 + 7
 x                    = 85
___________________
195 - (15x + 27) .39 = 4212         (dấu "[" đặt ở đấu tiên nên không cần thiết)
         (15x + 27) .39 = 195 - 4212
         (15x + 27) .39 = -4017
         (15x + 27)       = -4017 : 39
         (15x + 27)       = -103
          15x                 = -103 -27
          15x                 = -130
              x                 = -130 : 15
              x                 = -26/3
 

a) \(1045:\left[215-\left(3x-24\right)\right]=5\)

\(\Rightarrow215-\left(3x-24\right)=1045:5\)

\(\Rightarrow215-\left(3x-24\right)=209\)

\(\Rightarrow3x-24=215-209\)

\(\Rightarrow3x-24=6\)

\(\Rightarrow3x=6+24\)

\(\Rightarrow3x=30\)

\(\Rightarrow x=30:3\)

\(\Rightarrow x=10\)

Vậy x = 10

b) \(\left[195-\left(15x+27\right)\right]\times39=4212\)

\(\Rightarrow195-\left(15x+27\right)=4212:39\)

\(\Rightarrow195-\left(15x+27\right)=108\)

\(\Rightarrow15x+27=195-108\)

\(\Rightarrow15x+27=87\)

\(\Rightarrow15x=87-27\)

\(\Rightarrow15x=60\)

\(\Rightarrow x=60:15\)

\(\Rightarrow x=4\)

Vậy x = 4

_Chúc bạn học tốt_

`@` `\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