Question

Срочно!! помогите пожалуйста!! ДАМ 30 БАЛЛОВ!! 9 класс

Answer 1

$\displaystyle\bf\\1)\\\\\left \{ {{2x-12 > 0} \atop {3x > 9}} \right. \ \ \Rightarrow \ \ \left \{ {{2x > 12} \atop {x > 3}} \right. \ \ \Rightarrow \ \ \left \{ {{x > 6} \atop {x > 3}} \right. \ \ \Rightarrow \ \ x > 6\\\\2)\\\\\left \{ {{4y < -4} \atop {5-y > 0}} \right. \ \ \Rightarrow \ \ \left \{ {{y < -1} \atop {-y > -5} \right. \ \ \Rightarrow \ \ \left \{ {{y < -1} \atop {y < 5}} \right. \ \ \Rightarrow \ \ y < -1\\\\3)$

$\displaystyle\bf\\\left \{ {{3x-10 < 0} \atop {2x > 0}} \right. \ \ \Rightarrow \ \ \left \{ {{3x < 10} \atop {x > 0}} \right. \ \ \Rightarrow \ \ \left \{ {{x < 3\dfrac{1}{3} } \atop {x > 0}} \right. \ \ \Rightarrow \ \ x\in\Big(0 \ ; \ 3\frac{1}{3} \Big) \\\\4)\\\\\left \{ {{6y\geq 42} \atop {4y+12\leq 0}} \right. \ \ \Rightarrow \ \ \left \{ {{y\geq 7} \atop {4y\leq -12}} \right. \ \ \Rightarrow \ \ \left \{ {{y\geq 7} \atop {y\leq -3}} \right. \ \ \Rightarrow \ \ y\in\oslash$