Решите неравенство [latex] log_{x} \sqrt{21-4x} \ \textgreater \ 1[/latex]

[latex]Log_x( \sqrt{21-4x)}\ \textgreater \ 1 [/latex] ОДЗ:  [latex]21-4x\ \textgreater \ 0[/latex] [latex]4x\ \textless \ 21[/latex] [latex]x\ \textless \ 5.25[/latex] [latex]x\ \textgreater \ 0; x \neq 1[/latex] [latex]ODZ (0;1) (1;5.25)[/latex] 1 случай [latex]0\ \textless \ x\ \textless \ 1[/latex] [latex] \sqrt{21-4x}\ \textless \ x^1 [/latex] [latex]21-4x\ \textless \ x^2[/latex] [latex]x^2+4x-21\ \textgreater \ 0 D=16+84=100 x=-7; x=3 [/latex] Решений нет т.к. 0