Question

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

Answer 1

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