Question

CРОЧНО нужно решить несколько систем(прошу максимально подробно расписать решение):


{8x-2y=2

{-4x+4y=20


{1/3u - 1/5y=1

{15u-10u=9


{6m+3n=3

{2m-2n=4


{7x+y=20

{x-5y=8

Answer 1

Ответ:

$1)\left \{ {{8x-2y=2|*2} \atop {-4x+4y=20}} \right. \left +\{ {{16x-4y=4} \atop {-4x+4y=20}} \left \{ {{12x=24} \atop {-4x+4y=20}} \right. \right. \left \{ {{x=2} \atop {-4*2+4y=20}} \right. \left \{ {{x=2} \atop {-8+4y=20}} \right. \left \{ {{x=2} \atop {4y=28} \right. \left \{ {{x=2} \atop {y=7}} \right.$

$2)\left \{ {{\frac{1}{3}u-\frac{1}{5}y=1|*45 } \atop {15u-10y=9}} \right. -\left \{ {{15u - 9y=45} \atop {15u-10y=9}} \right. \left \{ {{y=36} \atop {15u-10y=9}} \right. \left \{ {{y=36} \atop {15u-360=9}} \right. \left \{ {{y=36} \atop {15u=369}} \right. \left \{ {{y=36} \atop {u=24.6} \right.$

$3)\left \{ {{6m+3n=3} \atop {2m-2n=4|*3}} \right. -\left \{ {6m+3n=3} \atop {6m-6n=12}} \right. \left \{ {9n=-9} \atop {6m-6n=12}} \right. \left \{ {{n=-1} \atop {6m-6n=12}} \right. \left \{ {{n=-1} \atop {6m-6*(-1)=12}} \right. \left \{ {{n=-1} \atop {6m+6=12} \right. \left \{ {{n=-1} \atop {6m=6}} \right. \left \{ {{n=-1} \atop {m=1}} \right.$

$4)\left \{ {{7x+y=20|*5} \atop {x-5y=8}} \right. +\left \{ {{35x+5y=100} \atop {x-5y=8}} \right. \left \{ {{36x=108} \atop {x-5y=8}} \right. \left \{ {{x=3} \atop {3-5y=8}} \right. \left \{ {{x=3} \atop {5y=-5}} \right. \left \{ {{x=3} \atop {y=-1}} \right.$

Объяснение: