Question

Решите неравенство:
3^4x-1 + 3^4x+1 больше или равно 80

Answer 1

$3^{4x-1}+3^{4x+1} geq 80 ~~~|cdot 3\ \ 3^{4x}+9cdot3^{4x} geq 240\ \ 10cdot3^{4x} geq 240\ \3^{4x} geq 24\ \ 4x geq log_324\ \ x geq log_3 sqrt[4]{24}$