Question

B) { x + 5y = 1
{ 3x - y = - 13
RESPONDE

C) { 2x + 3y = 0
{ 6x - 4y = 13
RESPONDE
D) { X= 3y - 1
{ 2x + y = 12
RESPONDE

Answer 1

B)

{ x + 5y = 1

{ 3x - y = - 13 (5)

x + 5y = 1

15x - 5y = - 65 (+)

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16x = - 64

x = - 64/16

x = - 4

x + 5y = 1

- 4 + 5y = 1

5y = 1 + 4

5y = 5

y = 5/5

y = 1

C)

{ 2x + 3y = 0 (-3)

{ 6x - 4y = 13

- 6x - 9y = 0

6x - 4y = 13 (+)

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- 13y = 13 (-1)

13y = - 13

y = - 13 / 13

y = - 1

2x + 3y = 0

2x = -3y

2x =- 3.(-1)

2x = 3

x = 3/2

D)

{ X= 3y - 1

{ 2x + y = 12

2x + y = 12

2.(3y - 1) + y = 12

6y - 2 + y = 12

7y =12+2

7y = 14

y = 14/7

y = 2

x = 3y - 1

x = 3.2 - 1

x = 6- 1

x = 5