2x + x - 12 = 0

=> 3x = 12

=> x = 4

vậy_

2x + x - 12 = 0

2x + x = 0 + 12

2x + x = 12

3x = 12

x= 12 : 3

x = 4

64 .6 + 81 . 4 + 17 . 6

= 6 . ( 64 + 17 ) + 81 . 4

= 6 . 91 + 81 . 4

= 546 + 324

= 870 

43 . 27 + 93 . 43 + 57 . 61 + 59 . 57

= ngày mai giải tiếp, đi ngủ đã !!!-_-^zzz

2x + x - 12 = 0 

<=> 2x + 1x - 12 = 0 

<=> 3x - 12 = 0 

<=> 3x = 0 + 12 

<=> 3x = 12 

<=> x = 12 : 3 

<=> x = 4

Vậy x = 4 

64 . 6 + 81 . 4 + 17 . 6 

= 64 . 6 + 17 . 6 + 81 . 4 

= 6 . ( 64 + 17 ) + 81 . 4 

= 6 . 81 + 81 . 4 

= 81 . ( 6 + 4 ) 

= 81 . 10 

= 810 

43 . 27 + 93 . 43 + 57 . 61 + 59 . 57 

= 43 . ( 27 + 93 ) + 57 . ( 61 + 59 ) 

= 43 . 129 + 57 . 120 

= 120 . ( 43 + 57 ) 

= 120 . 100 

= 12 000

     43 x 27 + 93 x 43 + 57 x 61 + 59 x 57 

  = 43 x ( 27 + 93 ) + 57 x ( 61 + 59 )

  =  43 x 120 +  57 x 120

  = 120 x ( 43 + 57 )

   = 120 x 100

  = 1200

b) 64 x 6 + 81 x 4 + 17 x 6 

 = 6 x ( 64 + 17 ) + 81 x 4 

 =  6 x 81 + 81 x 4 

 = 81 x ( 6 + 4 ) 

 = 81 x 10 

 = 810

A) =43 x (27+93)+57*(61+59)

=43*120+57*120

=120*(43+57)

=120*100

=12000

a, 119 + 24 + 81

= ( 119 + 81 ) + 24

= 200 + 24

= 224

b, 16 . 6 . 125

= 16 . 125 . 6

= 2000 . 6

= 12000

c, 25 . 104

= 25 . 100 + 25 . 4

= 2500 + 100

= 2600

d, 12 . 19 + 12 

= 12 . 19 + 12 . 1

= 12 . ( 19 + 1 )

= 12 x 20 

= 240

e, 43 . 27 + 93 . 43 + 57 . 61 + 59 . 57

= 43 . ( 27 + 93 ) + ( 61 + 59 ) . 57

= 43 . 120 + 120 . 57

= 120 . 43 + 120 . 57

= 120 . ( 43 + 57 )

= 120 . 100

= 12000

a/ 199 + 24 + 81 

= (119+81) + 24

= 200 + 24

= 224

b/ 16 . 6 . 125

= ( 16 . 125) . 6

= 2000 . 6

= 12000

c/ 25 . 104

= 25 . ( 100 + 4 )

= 25 . 100 + 25 . 4

= 2500 + 100

= 2600

d/43 . 27 + 93 . 43 + 57 . 61 + 59 . 57

= 43 . ( 27 + 93) + 57 . ( 61+ 59)

= 43 . 130 + 57 . 130

= (43 + 57) . 130

= 100 . 130

= 1300

Khiếp

2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40 
= 2. 53 . 9 . 3 + 2. 3 .9 .87 - 3 .2 .9 .40
= 54.53+54.87-54.40
=54(53+87-40)
=54. 100=5400

12 . 25 + 29 . 25 + 59 . 25 
= 25 . ( 12+29+59)
=25 . 90
=2250

43 . 37 + 93 . 43 + 57 . 61 + 69 . 57 
= 43.(37+93)+57(61+69)
=43.130+57.130
=130.(43+57)
=130.100
=13 000

12 . 53 + 53 . 172 - 53 
=53(12+172-1)
=53.184
=9752

35 . 54 + 35 . 58 + 65 . 75 + 65 . 45 
=35(54+58)+65(75+45)
=35.112+65.120
=3920+7800
=11720

39 . 8 + 70 . 3 + 31 . 8 
=8(39+31)+70.3
=8.70+70.3
=70.(8+3)
=70.11
=770

2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40

= ( 2 . 27 ) . 53 + ( 6 . 9 ) . 87 - ( 3 . 18 ) . 40

= 54 . 53 + 54 . 87 - 54 . 40

= 54(53+87-40)

= 5400

12 . 25 + 29 . 25 + 59 . 25

= 25( 12 + 29 + 59 )

= 2500

43 . 37 + 93 . 43 + 57 . 61 + 69 . 57

= 43( 37 + 93 ) + 57(61 + 69 )

= 5590 + 7410

= 13000

12 . 53 + 53 . 172 - 53 

= 53( 12 + 172 ) - 53

= 9752 - 53

= 9699

35 . 54 + 35 . 58 + 65 . 75 + 65 . 45

= 35( 54 + 58 ) + 65( 75 + 45 )

= 3920 + 7800

= 11720

300

300

= 300 

7 x 17 x 125 = (8 x 125) x 17 = 1000 x 17 = 17000

4 x 37 x 25 = (25 x 4 ) x 7 = 100 x 7 = 700

43 x 27 + 93 x 43 + 57 x 81 + 69 x 57 = 43 x (27 + 93) + 57 x (81 +69) = 43 x 120 + 57 x 120 + 57x30 = 120 x (43 + 57) + 1710 = 12000 + 1710 = 13710 

`@` `\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}`

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