Question

vcs poderiam me ajudar pfv? e pra amanhã ^^​

Answer 1

Resposta:

1.

x+y=15 x=15-y

x-y=1 x=15-7

x=9

(15-y)-y=1

-2y=1-15 (-1)

2y=14

y=7

_____________

2.

x+y=20 x=20-y

x-y=4 x=20-8

x=12

(20-y)-y=4

20-2y=4

-2y=4-20 (-1)

2y=16

y=8

_____________

3.

x-y=2 x=2+y

2x+y=7 x=2+3/11

x=2 3 = 22+3= 25

1 + 11 11 11

x=25/11

2(2+y) +y=7

4+3y=7

3y=7+4

3y=11

y=3/11

______//___________//____

espero ter ajudado :)

bons estudos !