Question

решить систему уравнения 
8х+3у=-21
4х+5у=-7

Answer 1

$left {{{8x+3y=-21} atop {4x+5y=-7 | * (-2)}} right. \ left { {{8x+3y=-21} atop {-8x-10y=14}} right. \ left { {{-7y=-7 | : (-7):} atop {8x+3y=-21}} right. \ left { {{y=1} atop {8x+3*1=-21}} right. \ left { {{y=1} atop {8x=-21-3}} right. \ left { {{y=1} atop {8x=-24 | :8}} right. \ left { {{y=1} atop {x=-3}} right.$
Ответ: (-3;1)

Answer 2

а откуда в третей строчке хоп и семёрки!?)))

Answer 3

первую

Answer 4

8х+3у=-21
4х+5у=-7

8х+3у=-21
4х+5у=-7|:(2)

8х+3у=-21
-8х-10у=14

-7у=-7|:(7)
У=1

8х+3=-21
8х=-3-21
8х=-24|:8
Х=-3


ОТВЕТ:(-3;1)