[tex]3^x = 243\\\text{Logaritm\u am cu }\log_3\text{ pentru ca x s\u anu mai fie exponent.}\\\log_33^x=\log_3243\\\text{Descompunem \^in factori primi: }\\243=3^5\\x\log_33=\log_33^5\\
x=5\log_33\\x=5[/tex]
[tex]7^{x-2}=128\\\text{Logaritm\u am cu }\log_7
\\128=2^7\\
\log_7(7^{x-2})=\log_72^7\\(x-2)\log_77=7\log_72\\x-2=8\log_72\\x=7\log_72+2[/tex]
