Question

[Best Friend Forever]

tìm các số tự nhiên n,a,b biết rang:

a, \(4^{15}.9^{15}< 2^n.3^n< 18^{16}.2^{16}\)

b\(2^n+342=7^b\)

Answer 1

[.]

a. \(4^{15}.9^{15}< 2^n.3^n< 18^{16}.2^{16}\)

\(\Rightarrow2^{30}.3^{30}< 2^n.3^n< \left(3^2\right)^{16}.2^{16}.2^{16}\)

\(\Rightarrow2^{30}.3^{30}< 2^n.3^n< 3^{32}.2^{32}\)

\(\Rightarrow30< n< 32\)

\(\Rightarrow n=31\)

Vậy : \(n=31\)

Answer 2

[zZz Cool Kid_new zZz]

\(n=0\Rightarrow b=3\)

Với \(n\ne0\Rightarrow VP⋮2butVT\) ko chia hết cho 2 nên ko thỏa mãn

Vậy \(n=0;b=3\)