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![](https://rs.olm.vn/images/avt/0.png?1311)
A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72
A = 78 x ( 31 + 24 + 17 ) + 22 x 72
A = 78 x 72 + 22 x 72
A = 72 x ( 78 + 22 )
A = 72 x 100
A = 7200
C = 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21
C = 39 x ( 53 + 47 ) - 21 x ( 53 - 47 )
C = 39 x 100 - 21 x 6
C = 3900 - 126
C = 3774
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 1 :
a) \(...=45\left(56+44\right)-500=45.100-500=4500-500=4000\)
b) \(...=3^2.6-6^{18}+1=45+1-6^{18}=46-6^{18}\)
c) \(...=756\left(66+48-14\right)=756.100=75600\)
d) \(...=8.15-\left(149-7^2\right)=120-\left(149-49\right)=120-100=20\)
Bài 2 :
a) \(x-21=46\Rightarrow x=21+46\Rightarrow x=87\)
b) \(2^x.4=128\Rightarrow2^x=32\Rightarrow2^x=2^5\Rightarrow x=5\)
c) \(3x+27=162\Rightarrow3x=162-27\Rightarrow3x=135\Rightarrow x=45\)
d) \(4x-8=4^{2023}.4^{2021}\)
\(\Rightarrow4x-8=4^{2023+2021}\)
\(\Rightarrow4x-8=4^{4044}\)
\(\Rightarrow4x=4^{4044}+8\)
\(\Rightarrow x=\left(4^{4044}+8\right):4\)
\(\Rightarrow x=4^{4043}+2\)
![](https://rs.olm.vn/images/avt/0.png?1311)
là biếng viết lời giải
1062
3700
40340
còn lời giải thích thì hỏi sau
a)997+86=997+3+83=1000+83=1083
b)37.(38+62)=37.100=3700
c)27.332+68.27+73.332+68.78
=27.332+73.332+68.27+68.78
=332.(27+73)+68.(27+78)
=332.100+68.105
=40340
![](https://rs.olm.vn/images/avt/0.png?1311)
a) `123 - 27 + 27 + 13 - 123`
`= (123 - 123) + (27 - 27) + 13`
`= 0 + 0 + 13`
`= 13`
`---`
b) `175 + 25 + 13 + 15 - 175 - 25`
`= (175-175)+(25-25)+25+13`
`=0+0+25+13`
`=28`
`---`
c) \(53\times39+47\times39+53\times21+47\times21\)
\(=\text{[}\left(53+47\right)\times39]+\left[\left(53+47\right)\times21\right]\)
\(=\left(100\times39\right)+\left(100\times21\right)\)
\(=3900+2100\)
`=6000`
`---`
d) \(49\times35+49\times16-49\times61\)
`=` \(49\times\left(35+16-61\right)\)
`=` \(49\times\left(-10\right)\)
`=-490`
![](https://rs.olm.vn/images/avt/0.png?1311)
a) (-37) + 15 - 30
= (-22) - 30
= (-22) + (-30)
= -52
b) -25 - 30 - 35
= -25 + (-30) + (-35)
= -55 + (-35)
= -90
c) 27 - 7 x (-3)
= 27 - (-21)
= 27 + 21
= 48
d) -15 x 5 + 17 - 6 x 4
= -75 + 17 - 24
= -58 - 24
= -58 + (-24)
= -82
a) (-37) + 15 - 30 = -52
b) - 25 - 30 - 35=-90
c) 27 - 7 x ( - 3 ) = 48
d) - 15 x 5 + 17 - 6 x 4 = -82
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 2010 - 2000 : [486 - 2(72 - 6)]
= 2010 - 2000 : [486 - 2(49 - 6)]
= 2010 - 2000 : [486 - 2 . 43]
= 2010 - 2000 : [486 - 86]
= 2010 - 2000 : 400
= 2010 - 5
= 2005
b) 2345 - 1000 : [19 - 2(21 - 18)2 ]
= 2345 - 1000 : [19 - 2 . 32 ]
= 2345 - 1000 : [19 - 18]
= 2345 - 1000 : 1
= 2345 - 1000
= 1345
c) 128 - [68 + 8(37 - 35)2 ] : 4
= 128 - [68 + 8 . 22 ] : 4
= 128 - [68 + 32 ] : 4
= 128 - 100 : 4
= 128 - 25
= 103
d) 568 - {5[143 - (4 - 1)2 ] + 10} : 10
= 568 - {5[143 - 9 ] + 10} : 10
= 568 - {5 . 134 + 10 } : 10
= 658 - {670 + 10 } : 10
= 658 - 680 : 10
= 658 - 68
= 590
a , 2014+(-1999)+1986+175+(-2001) = (2014+1986)+(-1999+-2001)+175
= 4000 + -4000 +175
= 175
roi tu lam nhe minh ban roi phai day
nice to meet you