Question

[LƯU THIÊN HƯƠNG]

\(\frac{1}{9}.3^4.3^n=3^7\)

\(\frac{1}{9}.27^n=3^n\)

\(\frac{1}{2}.2^n+4.2^n=9.5^n\)

32<2ⁿ <128

2.16 \(\ge\)  2ⁿ >4

Answer 1

[T.Ps]

#)Giải :

\(\frac{1}{9}.3^4.3^n=3^7\)

\(\frac{1}{9}.81.3^n=3^7\)

\(9.3^n=3^7\)

\(3^2.3^n=3^7\)

\(\Rightarrow2+n=7\)

\(\Rightarrow n=5\)

       #~Will~be~Pens~#

Answer 2

[T.Ps]

#)Giải :

\(\frac{1}{9}.27^n=3^n\)

\(\Leftrightarrow\frac{1}{9}=\frac{3^n}{27^n}\)

\(\Leftrightarrow\frac{1}{9}=\left(\frac{1}{9}\right)^n\)

\(\Leftrightarrow n=1\)

         #~Will~be~Pens~#