Question

Решите систему уравнений
2(x+5) = 9-3(4+y)
21+6x+4y = 4(2x+5)

Answer 1

2(х+5)=9-3(4+у)
21+6х+4у=4(2х+5)

2х+10=9-12-3у
21+6х+4у=8х+20

2х+3у=-13
-2х+4у=-1

3у=-13
4у=-1

7у=-14
у=-2

2х+3*(-2)=-13
2х-6=-13
2х=-7
х=-3,5
Ответ:(-3,5;-2)

Answer 2

2x+10=9-12-3y

21+6x+4y=8x+20

2x+3y=-13

-2x+4y=-1

7x=-14

x=-2

2*(-2)+3y=-13

-4+3y=-13

3y=-13+4

3y=-9

y=-3

(-2;-3)