Question

ПОМОГИТЕ ПОЖАЛУСТА
3.Какая из пар чисел является решением системы уравнений (фото)
4.Решите неравенство(фото)​

Answer 1

$\displaystyle\bf\\\left \{ {{x^{2} + y^{2}=10 } \atop {y-2x=5}} \right. \\\\\\\left \{ {{y=2x+5} \atop {x^{2} +(2x+5)^{2} =10}} \right.\\\\\\\left \{ {{y=2x+5} \atop {x^{2} +4x^{2} +20x+25-10=0}} \right. \\\\\\\left \{ {{y=2x+5} \atop {5x^{2} +20x+15=0 \ |:5}} \right. \\\\\\\left \{ {{y=2x+5} \atop {x^{2} +4x+3=0}} \right. \\\\\\\left \{ {{y=2x+5} \atop {\left[\begin{array}{ccc}x_{1} =-1\\x_{2} =-3\end{array}\right }} \right.$

$\displaystyle\bf\\\left[\begin{array}{ccc}\left \{ {{x_{1} =-1} \atop {y_{1} =2\cdot(-1)+5}} \right. \\\left \{ {{x_{2} =-3} \atop {y_{2} =2\cdot(-3)+5}} \right. \end{array}\right\\\\\\\left[\begin{array}{ccc}\left \{ {{x_{1} =-1} \atop {y_{1} =3}} \right. \\\left \{ {{x_{2} =-3} \atop {y_{2} =-1}} \right. \end{array}\right\\\\\\Otvet: \ \Big(-1 \ ; \ 3\Big) \ \ , \ \ \Big(-3 \ ; \ -1\Big)$

$\displaystyle\bf\\4)\\\\x^{2} -3x-4 > 0\\\\(x-4)(x+1) > 0\\\\\\+ + + + + (-1)- - - - - (4)+ + + + +$

//////////////                                 //////////////

Ответ :  x ∈ ( - ∞ ; - 1) ∪ (4 ; + ∞)