Xin lỗi bn , mk còn thiếu 1 câu :
\(8^{14}=4^N\)
\(\Rightarrow N=14.2\)
\(\Rightarrow N=28\)
a,\(8:2^N=2\)
\(2^N=8:2\)
\(2^N=4\)
\(2^N=2^2\)
b, \(8^n:2^n=4\)
\(\Rightarrow n=1\)
8 : 2^n=2
2^n = 8 : 2
2^n = 4 = 2^2
=> n=2
a,
8^14 = 2^3x14=2^42
4^n = 2^2n
=> 2^2n = 2^42
2n=42
n=21
b,
<=> (8:2)^n = 4
4^n=4
n=1