a,24.57+43.24

=24.(57+43)

=24.100

=2400

b,12.19+12

=12.(19+1)

=12.20

=12.10.2

=120.2

=240

c,43.27+93.43+57.61+59.57

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

=43.120+57.120

=120.(43+57)

=120.100

=12000

d,64.6+81.4+17.6

=64.6+27.3.2.2+17.6

=64.6+54.6+17.6

=(64+54+17).6

=135.6

=810

a) 24 . 57 + 43 . 24

= 24 . (57 + 43)

= 24 . 100

= 2400

b) 12 . 19 + 12

= 12 . (19 + 1)

= 12 . 20

=240

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

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

= 43 . 120 + 57 . 120

= 120 . (43 + 57)

= 120 . 100

= 12000

\(a,24\cdot57+43\cdot24\)

\(=24\cdot\left(57+43\right)\)

\(=24\cdot100=2400\)

\(b,12\cdot19+12\)

\(=12\cdot\left(19+1\right)\)

\(=12\cdot20=240\)

\(c,43\cdot27+93\cdot42+57\cdot61+59\cdot57\)

\(=43\cdot\left(27+93\right)+57\cdot\left(61+59\right)\)

\(=43\cdot120+57\cdot120\)

\(= \left(43+57\right)\cdot120\)

\(=100\cdot120=12000\)

\(d,64\cdot6+81\cdot4+17\cdot6\)

\(=\left(64+17\right)\cdot6+81\cdot4\)

\(=81\cdot6+81\cdot4\)

\(=81\cdot\left(6+4\right)\)

\(=81\cdot10=810\)

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

Mình bạn chép đề sai, đề bài như này mới đúng nhé, bạn check lại xem đề nha :

\(\frac{59-x}{41}+\frac{57-x}{43}+\frac{55-x}{45}=-3\)

\(\Leftrightarrow\frac{59-x}{41}+1+\frac{57-x}{43}+1+\frac{55-x}{45}+1=0\)

\(\Leftrightarrow\frac{100-x}{41}+\frac{100-x}{43}+\frac{100-x}{45}=0\)

\(\Leftrightarrow\left(100-x\right)\left(\frac{1}{43}+\frac{1}{45}+\frac{1}{41}\right)=0\)

\(\Leftrightarrow100-x=0\left(\frac{1}{41}+\frac{1}{43}+\frac{1}{45}\ne0\right)\)

\(\Leftrightarrow x=100\)

Vậy : \(x=100\)

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

\(\dfrac{59-x}{41}+\dfrac{57-x}{43}+\dfrac{55-x}{45}+\dfrac{53-x}{47}+\dfrac{51-x}{49}=-5\)

\(\Leftrightarrow\dfrac{59-x}{41}+1+\dfrac{57-x}{43}+1+\dfrac{55-x}{45}+1+\dfrac{53-x}{47}+1+\dfrac{51-x}{49}+1=0\)

=>100-x=0

hay x=100

ta có: (59-x)/41  +(57-x)/43  +(55-x)/45  +(53-x)/47  +(51-x)/49 =-5

       <=>[(59-x)/41  +1 ]  +[(57-x)/43  +1]  +[(55-x)/45  +1]  +[(53-x)/47  +1]   +[(51-x)/49  +1] =0

      <=>(59-x-41)/41      + (57-x-43)/43     +(55-x-45)/45     +(53-x-47)/47      +(51-x-49)/49    =0

      <=>(100-x)/41   +   (100-x)/43       +    (100-x)/45     +(100-x)/47      +   (100-x)/49   =0

     <=>(100-x).( 1/41   +  1/43  +  1/45   +   1/47   +  1/49  )  =0

mà   (1/41  +  1/43  +  1/45  +  1/47  +  1/49) khác 0  nên 100-x =0 <=>x=100

vậy nghiệm của pt là x=100