Cho biết: 1\(^3\)+2\(^3\)+3\(^3\)+....+10\(^3\)=3025
a/ 2\(^3\)+4\(^3\)+6\(^3\)+....+20\(^3\)
b/0,5+1\(^3\)+1,5\(^3\)+...+5\(^3\)
Những câu hỏi liên quan
Cho \(1^3+2^3+3^3+...+10^3=3025\)
Tính a) \(2^3+4^3+6^3+...+20^3\)
b)\(0,5^3+1^3+1,5^3+...+5^3\)
23 = (2.1)3 = 23. 13
43 = (2.2)3 = 23.23
63 = (2.3)3 = 23. 33
. . .
203 = (2.10) 3 = 23. 103
=> 23 + 43 + 63 +...+ 203
= 23. 13 + 23. 23 + 23. 33 + ... + 23 . 103
= 23. ( 13 + 23 + 33+ ... + 103)
= 23 . 3025
= 8. 3025
= 24200
So easyyyyyyyyyyyyyyyy
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Cho biết: \(1^3+2^3+3^3+....+10^3=1025\) Tính:
a) A = \(2^3+4^3+5^3+...+20^3\)
b) B = \(0,5^3+1^3+1,5^3+....+5^3\)
a) ta thấy 2^3 chia 1^3 = 8 => 8 lần cái biểu thức đề bài = A => A = 8 * 1025 = 8200
b) lại có 1^3 / 0.5^3 = 8 => 8B = cái biểu thức đề bài => B = 1025 / 8 = 128.125
Đ/S a) A = 8200
b) B=128.125
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Cho biết:
13+23+33+...+103=3025
Tính: a)A=23+43+63+...+203
b) B= 0,53+13+1,53+...+53
a) \(2^3+4^3+6^3+...+20^3\)
\(=2^3\left(1+2^3+...+10^3\right)\)
\(=8\cdot3025\)
\(=24200\)
b) \(0,5^3+1^3+1,5^3+...+5^3\)
\(=0,5^3\left(1+2^3+...+10^3\right)\)
\(=0,125\cdot3025\)
\(=378,125\)
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Bài 1: Tìm x :A) 3/4.(x-2) - 1/2.(6-2.x)= 1/6.x + 5
B) -1/2.(3.x + 5) - 2/3.(9-6.x) = 3/5.(x-10) - 3
C) (1/4.x - 1,5) + (5/6.x - 3) - (5/8.x -0,5) = -4,5
Bài 1: Tìm x : A) 25%x+4x=35-0,75x
B) 3/4.(x-2) - 1/2.(6-2x)=1/6x + 5
C) -1/2.(3x+5) - 2/3.(9-6x)= 3/5.(x-10) - 3
D) (1/4x - 1,5) + (5/6x-3) - (5/8x-0,5)= -4,5
1) 5/7.37 13/23-51 13/23.5/72) -2/3 +1/3+0,5+2 1/23)-0,5+2/3+1/24) (8+2 1/3-3/5) -(5+0,4)-(3 1/2 -2)5) (2/9-7/12):3/4+(16/9-5/12):3/46) -(2021.0,7+19,75) +0,7- (8-19,75)7)15/34+7/21+19/34-20/158) 2 5/6+1/6:(-5/8)9) (-2)^2 +2/9. (4/5-2/3)10) (-1/5+3/7):5/4+(-4/5+4/7):5/411) 2022,2021 . 1954,1945+ 2022,2021 . (-1954,1945)12) -5,2 .72 +69,1 +5,2 . (-28)+(-1,1)13) (7 -1/2-3/4) : (5-1/4-5/8)14) (8+ 2 1/3 -3/5) -(5+0,4) -( 3 1/3 - 2)
Đọc tiếp
1) 5/7.37 13/23-51 13/23.5/7
2) -2/3 +1/3+0,5+2 1/2
3)-0,5+2/3+1/2
4) (8+2 1/3-3/5) -(5+0,4)-(3 1/2 -2)
5) (2/9-7/12):3/4+(16/9-5/12):3/4
6) -(2021.0,7+19,75) +0,7- (8-19,75)
7)15/34+7/21+19/34-20/15
8) 2 5/6+1/6:(-5/8)
9) (-2)^2 +2/9. (4/5-2/3)
10) (-1/5+3/7):5/4+(-4/5+4/7):5/4
11) 2022,2021 . 1954,1945+ 2022,2021 . (-1954,1945)
12) -5,2 .72 +69,1 +5,2 . (-28)+(-1,1)
13) (7 -1/2-3/4) : (5-1/4-5/8)
14) (8+ 2 1/3 -3/5) -(5+0,4) -( 3 1/3 - 2)
`@` `\text {Ans}`
`\downarrow`
`1)`
`5/7*37 13/23 - 51 13/23*5/7`
`= 5/7* (37 13/23 - 51 13/23)`
`= 5/7* (-14)`
`= -10`
`2)`
`-2/3 +1/3+0,5+2 1/2`
`= -2/3 + 1/3 + 1/2 + 5/2`
`= (-2/3+1/3) + (1/2+5/2)`
`= -1/3 + 3`
`=8/3`
`3)`
`-0,5+2/3+1/2`
`= -1/2 + 2/3 + 1/2`
`= (-1/2 + 1/2) + 2/3`
`= 2/3`
`4)`
`(8+2 1/3-3/5) -(5+0,4)-(3 1/2 -2)`
`= 8+ 7/3 - 3/5 - 5 - 0,4 - 7/2 + 2`
`= (8+2-5) + (-3/5 - 2/5) + (7/3 - 7/2)`
`= 5 - 1 - 7/6`
`= 4 - 7/6 = 17/6`
`5)`
`(2/9-7/12):3/4+(16/9-5/12):3/4`
`= (2/9 - 7/12) \times 4/3 + (16/9 - 5/12) \times 4/3`
`= 4/3 *(2/9 - 7/12 + 16/9 - 5/12)`
`= 4/3 * [(2/9 + 16/9) + (-7/12 - 5/12)]`
`= 4/3 * ( 2 - 1)`
`= 4/3 * 1 = 4/3`
`6)`
`-(2021.0,7+19,75) +0,7- (8-19,75)`
`= -2021*0,7 -19,75 + 0,7 - 8 + 19,75`
`= 0,7*(-2021 + 1) - 8`
`= -1414-8`
`= -1422`
`7)`
`15/34+7/21+19/34-20/15`
`= (15/34 + 19/34) + 7/21 - 20/15`
`= 1 + 7/21 - 20/15`
`= 4/3 - 20/15 =0`
`8)`
`2 5/6+1/6:(-5/8)`
`= 17/6 + (-4/15)`
`= 77/30`
`9)`
`(-2)^2 +2/9. (4/5-2/3)`
`= 4 + 2/9*2/15`
`= 4+4/135`
`= 544/135`
`10)`
`(-1/5+3/7):5/4+(-4/5+4/7):5/4`
`= (-1/5+3/7) * 4/5 + (-4/5+4/7) * 4/5`
`= 4/5*(-1/5 +3/7-4/5+4/7)`
`= 4/5*[(-1/5-4/5)+(3/7+4/7)]`
`= 4/5* (-1+1)`
`= 4/5*0=0`
`11)`
`2022,2021 . 1954,1945+ 2022,2021 . (-1954,1945)`
`= 2022,2021 * [1954,1945 + (-1954,1945)]`
`= 2022,2021*0 `
`= 0`
`12)`
`-5,2 .72 +69,1 +5,2 . (-28)+(-1,1)`
`= -5,2*72 + 69,1 - 5,2*28 - 1,1`
`= -5,2*(72+28) + (69,1 - 1,1)`
`= -5,2*100 + 68`
`= -520 + 68`
`= -452`
`13)`
`(7 -1/2-3/4) : (5-1/4-5/8)`
`= 23/4 \div 33/8`
`=46/33`
`14)`
`(8+ 2 1/3 -3/5) -(5+0,4) -( 3 1/3 - 2)`
`= 8+ 2 1/3 - 3/5 - 5 - 0,4 - 3 1/3 + 2`
`= (8+2-5) + (2 1/3 - 3 1/3) - (0,6 + 0,4) `
`= 5 - 1 - 1`
`= 3`
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2: \(=\dfrac{-1}{3}+3=\dfrac{8}{3}\)
3: =1/2-1/2+2/3=2/3
5: \(=\dfrac{4}{3}\left(\dfrac{2}{9}-\dfrac{7}{12}+\dfrac{16}{9}-\dfrac{5}{12}\right)=\dfrac{4}{3}\)
12: \(=5.2\left(-72-28\right)+68=-520+68=-452\)
13: \(\dfrac{23}{4}:\dfrac{33}{8}=\dfrac{46}{33}\)
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1. Tính
a) (5/4)^3 . ( 4/5)^7
b) (1/3)4 . (-9/2)^6
c) 4^2 . (0.2)^3
d) (0,5)^4 . (-2)^8
e) (2/3)^3 . (8/27)^3
f) (9/10)^6 . (27/-20)^6
a, Cho biết: \(1^2+2^2+3^2+...+10^2=385\)
Tính A= \(3^2+6^2+9^2+...+30^2\)
b, Cho biết: \(1^3+2^3+3^3+...+10^3=3025\)
Tính B= \(2^3+4^3+6^3+...+20^3\)
a: A=3^2(1^2+2^2+...+10^2)
=9*385
=3465
b: B=2^3(1^3+2^3+...+10^3)
=8*3025
=24200
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Biết 13+23+33+...+103= 3025
Tính A= (0,5)3+13+(1,5)3+...+53
B= (0,25)3+(0,5)3+(0,75)3+...+(2,5)3