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\(\cdot DuyNam\)
\(A=-\dfrac{7}{21}+\left(1+\dfrac{1}{3}\right)\)
\(A=-\dfrac{7}{21}+\dfrac{4}{3}\)
\(A=1\)
\(B=\dfrac{2}{15}+\left(\dfrac{5}{9}+-\dfrac{6}{9}\right)\)
\(B=\dfrac{2}{15}+-\dfrac{1}{9}\)
\(B=\dfrac{1}{45}\)
\(C=\left(-\dfrac{1}{5}+\dfrac{3}{12}\right)+-\dfrac{3}{4}\)
\(C=\dfrac{1}{20}+-\dfrac{3}{4}\)
\(C=-\dfrac{7}{10}\)
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1.3.5...39/21.22.23...40=(1.3.5...39)(2.4.6...40)/(21.22...40)(2.4.6...40)
=1.2.3.4...40/21.22...40(1.2.3...40)2^20
=1/2^20
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1-2-3+4+5-6-7+8+...+21-22-23+24
= ( 1-2-3 + 4) + ( 5-6-7+8)+...+(21 -22- 23 +24)
= 0+0 +....+0
= 0
1 - 2 - 3 + 4 + 5 - 6 - 7 + 8 + . . . + 21 - 22 - 23 + 24
= ( 1 - 2 - 3 + 4 ) + ( 5 - 6 - 7 + 8 ) + . . . + ( 21 - 22 - 23 + 24 )
= 0 + 0 + . . . + 0
= 0
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3 ( x + 2 ) - 6 ( x - 5 ) = 2 ( 5 - 2x )
3 ( x + 2 ) - 6 ( x - 5 ) - 2 ( 5 - 2x ) = 0
3x + 6 - 6x + 30 - 10 + 4x = 0
( 3x - 6x + 4x ) + ( 6 + 30 - 10 ) = 0
x + 26 = 0
x = - 26
Vậy x = -26
\(3\left(x+ 2\right)-6\left(x-5\right)=2\left(5-2x\right)\)
\(3\left(x+2\right)-6\left(x-5\right)-2\left(5-2x\right)=0\)
\(3x+6-6x+30-10+4x=0\)
\(\left(3x-6x-4x\right)+\left(6+30-10\right)=0\)
\(x+26=0\)
\(x=0-26\)
\(x=-26.\)
Vậy x = -26.
#Nguyên
![](https://rs.olm.vn/images/avt/0.png?1311)
`-2/5 : x=1/2`
`=> x= -2/5 : 1/2`
`=> x= -2/5 xx 2`
`=>x= -4/5`
__
`7/6 : x = 7/4`
`=>x= 7/6 : 7/4`
`=>x=7/6 xx 4/7`
`=>x= 28/42`
`=>x=2/3`
![](https://rs.olm.vn/images/avt/0.png?1311)
A= [(1+101)x101:2]-(102-103)
A= 5151+1
A=5152
B= [1+(-3)]+[4+(-5)]+.......[101+(-103)]+105
B= (-2)+(-2)...........+(-2)+105
=> A>B
B=(-2)x26+105
B=(-56)+105
B= 49
cái => A>B nó nằm ở dưới cùng ấy. Nãy gõ chứ nó bị nhảy phím
mong các bạn giúp mình:)))))
-1/2 + 3/21 + -2/6 + -5/30
Ta tìm BCNN(2,21,6,30)
2=2
21=3.7
6=32
30=2.3.5
BCNN(2,21,6,30)= 32.5.7.2=630
: -1/2 + 3/21 + -2/6 + -5/30
= -315/630 + 90/630 + -210/630 + -105/630
=-315/630 + -105/630 + 90 + -210/630
= -420/630+ -120/630
= -540/630