Question

calcule os sistemas a)x+3y=13 b)2x+5y=23 c)x+y=8 d)2x+2y-22
x-y=5 x-y=1 x-y=2 x-y=3

Answer 1

Explicação passo-a-passo:

a)

x+3y=13

x-y=5 (-1)

x + 3y = 13

- x + y = - 5 (+)

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

4y = 8

Y = 8/4

Y = 2

x - y = 5

x - 2 = 5

x = 5 + 2

x = 7

b)

2x+5y=23

x - y=1 (-2)

2x + 5y = 23

- 2x + 2y = - 2 (+)

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

7y = 21

Y = 21/7

Y = 3

X - y = 1

x - 3 = 1

x = 1 + 3

x = 4

c)

x+y=8

x-y=2 (+)

-----------

2x = 10

x = 10/2

x = 5

x + y = 8

5 + y = 8

y = 8 - 5

y = 3

d)

2x+2y= - 22 (:2)

x - y = 3

x + y = - 11

x - y = 3 (+)

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

2x = - 8

x = - 8/2

x = - 4

x + y = - 11

- 4 + y = - 11

y = - 11 + 4

y = - 7