a) \(3^n:3^2=3^{n-2}\)
\(\Rightarrow3^{n-2}=3^5\)
\(\Rightarrow n=5+2=7\)
b) \(2^n-64=2^6\)
\(\Rightarrow2^n-2^6=2^6\)
\(\Rightarrow2^n=2\cdot2^6=2^7\)
\(\Rightarrow n=7\)
c) \(2^n:16=128\)
\(\Rightarrow2^n:2^{16}=2^{n-16}=128\)
\(2^{n-16}=2^7\)
\(\Rightarrow n=7+16=23\)
\(3^n:3^2=243\)
\(3^{n-2}=243\)
\(3^{n-2}=3^5\)
\(n-2=5\Leftrightarrow n=7\)
3^n:3^2=243
=> 3^n : 3^2 = 3^5
=> 3^n=3^5.3^2
=> 3^n=3^7
=> n=7
2^n:16=128
=> 2^n:2^4=2^7
=> 2^n=2^7.2^4
=> 2^n=2^11
=> n=11
Ta có
3^n :3^2 =243
=> 3^n :3^2 =3^5
=>n-2=5
=>n=7
2^n:64=2^6
=>2^n :2^6=2^6
=>n-6=6
=>n=12
2^N :16=128
=>2^n:2^4=2^7
=>n-4=7
=>n=11
Thế bận nhé
3n : 32 = 243
3n : 9 =243
3n = 243 : 9
3n = 27
ta thấy 33 = 27
\(\Rightarrow\)n=3
2n- 64=26
2n-64=64
2n = 64+64
2n =128
ta có 27 = 128
\(\Rightarrow\)n=7
2n : 16= 128
2n = 128:16
2n = 8
ta có 23 = 8
\(\Rightarrow\)n=3
3 ^ n : 3 ^ 2 = 243
3 n-2 = 35
\(\Rightarrow\)n - 2 = 5
\(\Rightarrow\) n = 7
2 ^ n - 64 = 2 ^ 6
2n = 64 + 64
2n = 128 = 27
\(\Rightarrow\)n = 7
2 ^ n : 16 = 128
2n : 24 = 27
2n = 27 x 24
2n = 211
\(\Rightarrow\)n = 11 .
