Question

Решите неравенство:
1/27 < 3^(2−x) ≤ 27.

Answer 1

$\frac{1}{27}\ \textless \ 3^{2-x} \leq 27\\\\3^{-3}\ \textless \ 3^{2-x} \leq 3^3\\3\ \textgreater \ 1\\\\-3\ \textless \ 2-x \leq 3\\\\-3-2\ \textless \ -x \leq 3-2\\\\-5\ \textless \ -x \leq 1\; \; |:(-1)\\\\5\ \textgreater \ x \geq -1\\\\-1 \leq x\ \textless \ 5\\\\x\in[-1;5)$