Verified answer

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E'fazer iguais as duas equacoes

a)7x-y-15=o ==> Y = 7X - 15

x-y+7=0 ====> Y = X + 7

7X - 15 = X + 7

6X = 7 +15

X = 22/6 = 11/3 =====> Y = X+7 ==> Y = 11/3 + 7 ===> Y = 32/3

resp. a) ( 11/3 , 32/3)

as outras sao semelhantes, é so isolar Y e igualar as equacoes.

a)

7x - y = 15

x - y = -7

6x = 22

x = 11/3

y = x + 7

y = 11/3 + 21/3 = 32/3

P(11/3, 32/2)

b)

-2x + 3y = -8,

-5x - 2y = -1

-4x + 6y = -16

-15x - 6y = -3

-19x = -19

x = 1

2y = -5x + 1 = -5 + 1 = -4

y = -2

P(1,-2)

c)

6x - 5y = 12,

4x + 5y = 8

10x = 20

x = 2

12 - 5y = 12

5y = 0

y = 0

P(2,0)

d)

5x + 3y = 35

5x - 10y = -30

-5x + 10y = 30

13y = 65

y = 5

5x + 15 = 35

5x = 20

x = 4

P(4,5)

e)

7x - 2y = 41,

-2x + 3y = 19

21x - 6y = 123

-4x + 6y = 38

17x = 161

x = 161/17

y = 215/17

P(161/17, 215/17)

pronto