Решить систему неравенств: 1) {3х>-9 {х>-1 2) {2х+7≥4х-8 {10+4х>0 Решить систему...

-9} \atop {x>-1}} \right.\\\\\left \{ {{x>-3} \atop {x>-1}} \right." alt="1)\left \{ {{3x>-9} \atop {x>-1}} \right.\\\\\left \{ {{x>-3} \atop {x>-1}} \right." align="absmiddle" class="latex-formula">

Ответ : x ∈ (-1 ; + ∞)

0}} \right.\\\\\left \{ {{2x-4x\geq-8-7 } \atop {4x>-10}} \right.\\\\\left \{ {{-2x\geq-15 } \atop {x>-2,5}} \right. \\\\\left \{ {{x\leq7,5 } \atop {x>-2,5}} \right." alt="2)\left \{ {{2x+7\geq4x-8 } \atop {10+4x>0}} \right.\\\\\left \{ {{2x-4x\geq-8-7 } \atop {4x>-10}} \right.\\\\\left \{ {{-2x\geq-15 } \atop {x>-2,5}} \right. \\\\\left \{ {{x\leq7,5 } \atop {x>-2,5}} \right." align="absmiddle" class="latex-formula">

Ответ : x ∈ (- 2,5 ; 7,5]

$3)\left \{ {{x+2y=-2} \atop {3x-y=8}|*2} \right.\\\\+\left \{ {{x+2y=-2} \atop {6x-2y=16}} \right. \\ ---------\\\\7x=14\\\\x=2\\\\y=3x-8=3*2-8=6-8=-2$

Ответ : (2 , -2)