X^2+sqrt(x^2+11) меньше 31

[latex]\sqrt{x^{2}+11}=t, t \geq 0[/latex] [latex]x^{2}=t^{2}-11[/latex] [latex]t^{2}-11+t-31<0[/latex] [latex]t^{2}+t-42<0[/latex] [latex](t+7)(t-6)<0[/latex] [latex]-7 < t < 6[/latex] [latex]-7 < \sqrt{x^{2}+11} < 6[/latex] [latex]0 \leq \sqrt{x^{2}+11} < 6[/latex] [latex] \left \{ {{\sqrt{x^{2}+11} \geq 0} \atop {\sqrt{x^{2}+11} < 6}} \right. [/latex] [latex] \left \{ {{x^{2}+11 \geq 0} \atop {\x^{2}+11 < 36}} \right. [/latex] [latex]x^{2}-25<0[/latex] [latex](x-5)(x+5)<0[/latex] [latex]-5