Question

Помоги срочно пожалуйста

Answer 1

$1. \left \{ {{2x-3y=8} \atop {3x+y=1}} \right. \{ {{2x-3y=8} \atop {y=1-3x}} \right. \\\\2x-3(1-3x)=8\\2x-3+9x=8\\2x+9x=8+3\\11x=11\\x=1\\\\y=1-3*1\\y=1-3\\y=-2\\\\(1;-2)$

$2. \left \{ {{12-10(2x-1)=-6(4y-3)} \atop {0.4y+0.6x=4.6}} \right. \left \{ {{12-20x+10=-24y+18} \atop {0.4y+0.6x=4.6}} \right. \left \{ {{-20x+24y=-4|:(-4)} \atop {0.4y+0.6x=4.6|*15}} \right.\left \{ {{5x-6y=1} \atop {6y+9x=69}} \right. \\\\5x-6y+6y+9x=69+1\\14x=70\\x=5\\\\5*5-6y=1\\25-6y=1\\-6y=-25+1\\-6y=-24\\y=4\\\\(5;4)$

Answer 2

$\displaystyle\bf\\1)\\\\\left \{ {{2x-3y=8} \atop {3x+y=1}} \right. \\\\\\\left \{ {{2x-3\cdot(1-3x)=8} \atop {y=1-3x}} \right. \\\\\\\left \{ {{2x-3+9x=8} \atop {y=1-3x}} \right. \\\\\\\left \{ {{11x=8+3} \atop {y=1-3x}} \right.\\\\\\\left \{ {{11x=11} \atop {y=1-3x}} \right.\\\\\\\left \{ {{x=1} \atop {y=1-3\cdot 1}} \right.\\\\\\\left \{ {{x=1} \atop {y=-2}} \right.\\\\\\Otvet:(1 \ ; \ -2)$

$\displaystyle\bf\\2)\\\\\left \{ {{12-10(2x-1)=-6(4y-3)} \atop {0,4y+0,6x=4,6}} \right. \\\\\\\left \{ {{12-20x+10=-24y+18} \atop {0,6x+0,4y=4,6}} \right. \\\\\\\left \{ {{-20x+24y=18-22} \atop {0,6x+0,4y=4,6}} \right.\\\\\\\left \{ {{-20x+24y=-4 \ |:(-4)} \atop {0,6x+0,4y=4,6 \ |\cdot 5}} \right.\\\\\\\left \{ {{5x-6y=1} \atop {3x+2y=23 \ |\cdot3}} \right.\\\\\\+\left \{ {{5x-6y=1} \atop {9x+6y=69}} \right.\\---------\\14x=70\\\\x=5$

$\displaystyle\bf\\2y=23-3x=23-3\cdot5=23-15=8\\\\y=8:2=4\\\\\\Otvet \ : \ (5 \ ; \ 4)$