3^-1 . 3^n + 5.3^n-1 =162 help me, please!!!!!!!! :)))

0 bình luận về “3^-1 . 3^n + 5.3^n-1 =162 help me, please!!!!!!!! :)))”

1. Đáp án:

   \(n=4\)

   Giải thích các bước giải:

   \(\begin{array}{l}
   {3^{ – 1}}{.3^n} + {5.3^{n – 1}} = 162\\
   {3^{n – 1}} + {5.3^{n – 1}} = 162\\
   {3^{n – 1}}\left( {1 + 5} \right)\,\,\,\,\, = 162\\
   {3^{n – 1}}.6\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 162\\
   {3^{n – 1}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 162:6\\
   {3^{n – 1}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 27\\
   {3^{n – 1}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = {3^3}\\
   n – 1\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 3\\
   n\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 3 + 1\\
   n\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 4
   \end{array}\)

   Trả lời

2. Đáp án:

   Giải thích các bước giải:

   <=>3^n-1+5.3^n-1=162

   <=>3^n-1(1+5)=162

   <=>3^n-1.6=162

   <=>3^n-1=3^3

   <=>n-1=3

   <=>n=4

   Trả lời