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\(9^{5-2x}=729\)
\(9^{5-2x}=3\)
\(5-2x=3\)
\(2x=5-3\)
\(2x=2\)
\(x=2:2\)
\(x=1\)
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5x+1 - 5x = 100
5x. 5 - 5x . 1 = 100
5x . ( 5 - 1 ) = 100
5x . 4 = 100
5x =100 : 4
5x = 25
5x= 52
=> x = 2
2)
92x : 9 = 729
92x : 91 = 729
92x-1 = 729
92x-1 = 93
=> 2x - 1 = 3
2x = 3 + 1
2x = 4
=> x = 4 : 2
x = 2
MÌNH LÀM CÂU 2 THÔI NHÉ
92X:9=729
92X=729:9
92X=81
92X=92
SUY RA; 2.X=2
X=2:2
X=1
Vậy x=1
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a) 92x : 9 =729 <---> 92x=729.9 <--->92x=6561 <---->92x=92.2--->x=2
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\(9^{2x-1}=729=9^3\Leftrightarrow2x-1=3\Leftrightarrow2x=4\Leftrightarrow x=2\)
Trả lời :............................................
\(9^{2x-1}=729=9^3\Leftrightarrow2x-1=3\Leftrightarrow2x=4\Leftrightarrow x=2\)
Hk tốt,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
k nhé Kiet nguyen
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a, không có x :v
b, (2x + 1)3 = 729
=> (2x + 1)3 = 93
=> 2x + 1 = 9
=> 2x = 8
=> x = 4
vậy_
c, 97 : x = 97
=> x = 97 : 97
=> x = 1
vậy_
d, x5 : 83 = 64
=> x5 : 83 = 82
=> x5 = 82.83
=> x5 = 85
=> x = 8
vậy_
a) 3x : 3 = 81
3x = 27 = 33
=> x = 3
b) (2x+1)3 = 729 = 93
=> 2x + 1 = 9
2x = 8
x = 4
c) 97: x = 97
x = 1
d) x5 : 83 = 64 = 82
x5 = 83.82 = 85
=> x = 8
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\(=\dfrac{3\cdot7\cdot3^4\cdot3^6+3^6\cdot3^4\cdot3^3}{3^2\cdot3^4\cdot2\cdot3^{12}\cdot13+3^2\cdot2\cdot3^3\cdot2\cdot3^4\cdot2\cdot3^2+723\cdot729}\)
\(=\dfrac{3^{11}\cdot7+3^{13}}{3^{18}\cdot26+3^{11}\cdot8+3^7\cdot241}\)
\(=\dfrac{3^{11}\left(7+9\right)}{3^7\left(3^{11}\cdot26+3^4\cdot8+241\right)}=\dfrac{3^7\cdot16}{17\cdot101\cdot2683}\)
\(9^5-2x=729\)
\(\Rightarrow9^5-2x=9^3\)
\(\Rightarrow2x=9^3\times\left(9^2-1\right)\)
\(\Rightarrow2x=9^3\times80\)
\(\Rightarrow2x=58320\)
\(\Rightarrow x=\text{29160}\)
~Std well~
P/s: Chắc sai :v