1. Сколько решений имеет система уравнений [latex] \left \{ {{x^2+y^2=9} \atop {y=x^2}} \right. [/latex] 2. Найдите область определения выражения [latex] \sqrt{\frac{x^2-25}{x^2+x+7}}[/latex]

[latex]1)\; \left \{ {{x^2+y^2=9} \atop {y=x^2}} \right. \; \left \{ {{x^2+x^2=9} \atop {y=x^2}} \right. \; \left \{ {{x^2}=\frac{9}{2} \atop {y=x^2}} \right. \; \left \{ {{x=\pm \frac{3}{\sqrt2}} \atop {y=\frac{9}{2}}} \right. \\\\Otvet:\; \; (-\frac{3}{\sqrt2};\frac{9}{2})\; ,\; (\frac{3}{\sqrt2};\frac{9}{2})\; .\\\\2)\; \; \sqrt{\frac{x^2-25}{x^2+x+7}}\\\\ODZ:\; \; \frac{x^2-25}{x^2+x+7} \geq 0\\\\x^2+x+7\ \textgreater \ 0\; ,\; tak\; kak\; \; D=1-4\cdot 7=-27\ \textless \ 0\; \Rightarrow \\\\x^2-25 \geq 0\\\\(x-5)(x+5) \geq 0[/latex] [latex]+++[-5\, ]---[\, 5\, ]+++\\\\x\in (-\infty ,-5\, ]\cup [\, 5,+\infty )[/latex]