Question

Решите уравнение:

3^x-2*3^x-2=7

Answer 1

$displaystyle 3^x-2*3^{x-2}=7\\3^x=t; t textgreater 0\\t- frac{2}{3^2}t=7\\9t-2t=63\\7t=63\\t= 9\\3^x=9\\x=2$