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![](https://rs.olm.vn/images/avt/0.png?1311)
42 + 43 + 44 + 45 - 32 - 33 - 34 - 35
= (42 - 32)+(43 - 33)+(44 - 34)+(45 - 35)
= 10+10+10+10
= 40
(64+65+66+67+68) - (54+55+56+57+58)
= 64+65+66+67+68 - 54-55-56-57-58
= (64 - 54)+(65 - 55) +(66 - 56) + (67- 57) + (68 -58)
= 10+10+10+10+10
= 50
![](https://rs.olm.vn/images/avt/0.png?1311)
\(27.332+93.43+57.61+69.57\\ =27.332+93.43+57.\left(61+69\right)\\ =27.332+93.43+57.130\\ =8964+3999+7410=20373\\ 34.75+75.66-65.100\\ =\left(34+66\right).75-65.100\\ =100.75-65.100\\ =100.\left(75-65\right)\\ =100.10=1000\\ \left(456.11+912\right).37:13:74\\ =5928:13:\left(74:37\right)\\ =456:2=228\\ 6^2:4.3+2.5^2\\ =36:4.3+2.25\\ =9.3+50=27+50=77\\ 5.4^2-18:3^2\\ =5.16-18:9\\ =80-2=78\\\left[\left(315+372\right).3+\left(372+315\right).7\right]:\left(26.13+74.14\right)\\ =687.\left(3+7\right):\left(338+1036\right)\\ 687.10:1374\\ =6870:1374=5\\ 12:\left\{390:\left[500-\left(125+35.7\right)\right]\right\}\\ =12:\left[390:\left(500-370\right)\right]\\ =12:\left(390:130\right)=12:3=4\\ 192000-\left(1500.2+1800.3+1800.2:3\right)\\ =192000-\left(3000+5400+1200\right)\\ =192000-9600=182400\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a,1-3+5-7+9-.......+33-35
=(1+5+9+....+33)-(3+7+11+...+35)
=153-171
=-18
Tick mk vài cái lên 300 mk giải nốt phần b
![](https://rs.olm.vn/images/avt/0.png?1311)
1) 42/35 - [ 33/14 . 21/22 - ( 54/25 : 27/25 - 7/10 )]
= 42/35 - ( 9/4-13/10)
=42/35-19/20
=1/4
2) a) 5/21 . x/34 = 35/102
x/34=35/102 : 5/21
x/34=49/34
=> x=34
Vậy x=34
b) 15/x . 21/13 = 45/91
15/x=45/91 : 21/13
15/x=15/49
=> x=49
Vậy x=49
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,2^2=4,2^3=8,2^4=16,2^5=32,2^6=64,2^7=128,2^8=256,2^9=512,2^{10}=1024\)
\(b,3^2=9,3^3=27,3^4=81,3^5=243\)
\(c,4^2=16,4^3=64,4^4=256\)
\(d,5^2=25,5^3=125,5^4=625\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 1:
a) Ta có: \(x\left(x^2-4\right)=0\)
\(\Leftrightarrow x\left(x-2\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x-2=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)
Vậy: \(x\in\left\{0;2;-2\right\}\)
b) Ta có: \(\left(2x-3\right)+\left(-3x\right)-\left(x-5\right)=40\)
\(\Leftrightarrow2x-3-3x-x+5=40\)
\(\Leftrightarrow-2x+2=40\)
\(\Leftrightarrow-2x=38\)
hay x=-19
Vậy: x=-19
Bài 2:
a) Ta có: \(-45\cdot12+34\cdot\left(-45\right)-45\cdot54\)
\(=-45\cdot\left(12+34+54\right)\)
\(=-45\cdot100\)
\(=-4500\)
b) Ta có: \(43\cdot\left(57-33\right)+33\cdot\left(43-57\right)\)
\(=43\cdot57-43\cdot33+43\cdot33-33\cdot57\)
\(=43\cdot57-33\cdot57\)
\(=57\cdot\left(43-33\right)\)
\(=57\cdot10=570\)
![](https://rs.olm.vn/images/avt/0.png?1311)
bài 3 : tính nhanh
a) (42*43+43*57+43)-360:4
ngoặc vuông43.(42+57+1) ngoặc vuông -90
43.100-90
4300-90
4210
b.
a) (42*43 + 43*57 + 43) - 360:4
= 43*(42+57+1) - 90
= 43*100 - 90
= 4300 - 90
= 3410
( Mình đang học zoom nên bạn chờ mình chút để mình làm nốt phần còn lại nhé ! )
a) A= 1+32+34+......+32020
=> 32A = 3 + 32+34+......+32022
=> 32A - A = ( 3 + 32+34+......+32022 ) - ( 1+32+34+......+32020 )
=> 9A - A = 32022 - 1
=> 8A = 32022 - 1
=> A = ( 32022 - 1 ) : 8
A= 1+3^2+3^4+......+3^2020
6A= 3^2+3^4+3^6+......+3^2022
6A-A=(3^2+3^4+3^6+......+3^2022)-(1+3^2+3^4+......+3^2020)
5A=3^2022-1
A=(3^2022-1):5