\(a,3^2\cdot3^4\cdot3^n=3^{12}\)
\(\Rightarrow3^{6+n}=3^{12}\)
\(\Rightarrow6+n=12\)
\(\Rightarrow n=6\)
\(b,2^n:4=16\)
\(\Rightarrow2^n:2^2=2^4\)
\(\Rightarrow2^{n-2}=2^4\)
\(\Rightarrow n-2=4\)
\(\Rightarrow n=6\)
\(c,6\cdot2^n+3\cdot2^n=9\cdot2^9\)
\(\Rightarrow2^n\left(6+3\right)=9\cdot2^9\)
\(\Rightarrow2^n\cdot9=9\cdot2^9\)
\(\Rightarrow2^n=2^9\)
\(\Rightarrow n=9\)
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a)32.34.3n=312
32+4.3n=312
36.3n=312
suy ra:6+n=12
n=6.
Vậy n=6
b)2n:4=16
2n=16.4
2n=64
2n=26
Vậy n=6
c)6.2n+3.2n=9.29
(6+3).2n=9.29
9.2n=9.29
suy ra:n=9
Vậy n=9
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