Question

me ajudem!!!!!!!!!

1. Resolva os sistemas

a) {x + y= 7
{x - y =3


b) {x + y = 2
{2x - y = 1


c) {3x + 5y = 11
{5x – 5y = 5


d) {x + y = 7
{-x + y = -5

Answer 1

Explicação passo-a-passo:

a) {x + y= 7

{x - y =3

y = 7 - 1x

y = (7 - 1x)/(1)

x - 1(7 - 1x)/(1) = 3

x + (-7 + 1x)/(1) = 3

x - 7 + 1x = 3

2x = 10

x = 5

y = (7 -1 . 5)

y = (7 - 5)

y = 2

S = {(5, 2)}

b) {x + y = 2

{2x - y = 1

y = 2 - 1x

y = (2 - 1x)/(1)

2x - 1(2 - 1x)/(1) = 1

2x + (-2 + 1x)/(1) = 1

2x - 2 + 1x = 1

3x = 3

x = 1

y = (2 -1 . 1)

y = (2 - 1)

y = 1

S = {(1, 1)}

c) {3x + 5y = 11

{5x – 5y = 5

5y = 11 - 3x

y = (11 - 3x)/(5)

5x - 5(11 - 3x)/(5) = 5

5x + (-55 + 15x)/(5) = 5

25x - 55 + 15x = 25

40x = 80

x = 2

y = (11 -3 . 2) / 5

y = (11 - 6) / 5

y = 5/5

y = 1

S = {(2, 1)}

d) {x + y = 7

{-x + y = -5

y = 7 - 1x

y = (7 - 1x)/(1)

-x + 1(7 - 1x)/(1) = -5

-x + (7 - 1x)/(1) = -5

-x + 7 - 1x = -5

-2x = -12

x = 6

y = (7 -1 . 6)

y = (7 - 6)

y = 1

S = {(6, 1)}