Verified answer

28+7x=2y-6

7x-2y=-6-28

7x-2y=-34

-4x-4y=7-y

-4x-4y+y=7

-4x-3y=7

sistema

7x-2y=-34 (.4)

-4x-3y=7 (.7)

28x-8y=-136

-28x-21y=49

---------------

/ -29y=--87

y=3

7x-2(3)=-34

7x=-34+6

x=-28/7

x=-4 (-4,3)

7*(4 + x) = 2*(y - 3)

28 + 7x = 2y - 6

2y - 7x = 34

4*(-x - y) = 7 - y

-4x - 4y = 7 - y

3y + 4x = -7

sistema

2y - 7x = 34

3y + 4x = -7

6y - 21x = 102

6y + 8x = -14

29x = -116

x = -4

2y - 7x = 34

2y + 28 = 34

2y = 6

y = 3

S = { (x,y) ,(-4,3) }

pronto

28+7x=2y-6

7x-2y=-34

-4x-4y=7-y

-4x-3y=7

7x-2y=-34

-4x-3y=7

7(4+x)=2(y-3)

4(-x-y)=7-y

28+7x=2y-6

7x-2y=-28-6

7x-2y=-34

-4x-4y=7-y

-4x-4y+y=7

-4x-3y=7

{7x-2y=-34

{-4x-3y=7

Agora vc pode aplicar a regra mais conveniente.