Question

Решите систему уравнений

Answer 1

$\left \{ {{7^{x-1}(7+1) \geq 56} \atop {5^{-x}*5^2\ \textgreater \ 5^{-x^2}}} \right. \\\\ \left \{ {{7^{x-1} \geq 7} \atop {5^{2-x}\ \textgreater \ 5^{-x^2}}} \right. \\\\ \left \{ {{x-1 \geq 1} \atop {2-x\ \textgreater \ -x^2}} \right. \\\\ \left \{ {{x \geq 2} \atop {x^2-x+2\ \textgreater \ 0}} \right. \\\\ D=1-8\ \textless \ 0=\ \textgreater \ x\in R\\\\ OTBET:x\in[2;+\infty)$