Question

8 класс, 2 рівняння......

Answer 1

Ответ:

1064.1) -1;2.

1064.2)3;2

Объяснение:

1){7х+2у=-3

{-14х+3у=20;

{14х+4у=-6

{-14х+3у=20

7у=14

7х+2у=-3

у=2

7х+4=-3

у=2

7х=-7

х=-1

у=2

Ответ: -1;2.

2)3х+5у=19

7х-10у=1

6х+10у=38

7х-10у=1

13х=39

7х-10у=1

х=3

21-1=10у

х=3

у=2

Ответ:3;2.

Answer 2

$\displaystyle\bf\\1)\\\\\left \{ {{7x+2y=-3} \ |\cdot 2\atop {-14x+3y=20}} \right. \\\\\\+\left \{ {{14x+4y=-6} \atop {-14x+3y=20}} \right. \\-----------\\7y=14\\\\y=2\\\\7x=-2y-3=-2\cdot 2-3=-4-3=-7\\\\x=-7:7=-1\\\\Otvet: \ (-1 \ ; \ 2)\\\\\\2)\\\\\left \{ {{3x+5y=19} \ |\cdot 2\atop {7x-10y=1}} \right. \\\\\\+\left \{ {{6x+10y=38} \atop {7x-10y=1}} \right. \\----------\\13x=39\\\\x=3\\\\5y=19-3x=19-3\cdot 3=19-9=10\\\\y=10:5=2\\\\Otvet: \ (3 \ ; \ 2)$