tìm x: 1000 - x = 645
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1, \(x^3+3^3=\left(x+3\right)\left(x^2-3x+9\right)\)
2, đề sai
3, \(x^3+8=\left(x+2\right)\left(x^2-2x+4\right)\)
4, \(x^3-64=\left(x-4\right)\left(x^2+4x+16\right)\)
5, \(1000-y^3=\left(10-y\right)=\left(100+10y+y^2\right)\)
tương tự ...
8, \(8x^3+27y^3=\left(2x+3y\right)\left(4x^2-6xy+9y^2\right)\)
Câu 2 đề ko sai nha bạn.
2) x2 - (\(\sqrt{y^3}\))2 ( y>0)
= ( x -\(\sqrt{y^3}\)) ( x +\(\sqrt{y^3}\))
![](https://rs.olm.vn/images/avt/0.png?1311)
X x 25=645+255
X x 25=900
X=900:25
x=36 k mk ~mk k lại !!!
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A = 512 x 4 + 512 x 58
A = 512 x (4 + 58)
A = 512 x 62
A = 31 744
B = 312 x 36 - 312 x 26
B = 312 x (36 - 26)
B = 312 x 10
B = 3120
C = 745 x 11 - 745
C = 745 x (11 - 1)
C = 745 x 10
C = 7450
D = 837 x 15 - 837 x 5
D = 837 x (15 - 5)
D = 837 x 10
D = 8370
E = 578 x 78 - 578 x 14 + 578 x 36
E = 578 x (78 - 14 + 36)
E = 578 x 100
E = 57 800
F = 645 x 78 + 645 x 22
F = 645 x (78 + 22)
F = 645 x 100
F = 64 500
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a) \(5^{x+3}+5^{x+1}-5^x=645\)
\(\Rightarrow5^x.5^3+5^x.5-5^x=645\)
\(\Rightarrow5^x.\left(5^3+5-1\right)=645\)
\(\Rightarrow5^x.129=645\)
\(\Rightarrow5^x=5\)
\(\Rightarrow x=1\)
Vậy \(x=1\)
b) \(9.27\ge3^x\ge243\)
\(\Rightarrow3^2.3^3\ge3^x\ge3^5\)
\(\Rightarrow3^5\ge3^x\ge3^5\)
\(\Rightarrow5\ge x\ge5\)
\(\Rightarrow x=5\)
Vậy \(x=5\)
![](https://rs.olm.vn/images/avt/0.png?1311)
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a , x = − 6532 x = − 8965 x = 8520 b , x = 7984 x = 465 x = − 645
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1000 +1000 +1000 +1000 + x = 5000
4000 + x = 5000
x = 5000 - 4000
x = 1000
1000+1000+1000+1000+x=5000
1000*4+x=5000
4000+x=5000
x=5000-4000
x=1000
1000 - x = 645
x = 1000 - 645
x = 355
1000 - x = 645
x =1000-645
x =355