Question

Resolva os sistemas abaixo:
a) x+y=13
x-y=1

b) x+y=19
2x-y=11


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Answer 1

Explicação passo-a-passo:

x+y=13

x-y=1

x=13-y

13-y-y=1

13-2y=1

-2y=1-13

-2y=-12

2y=12

y=12/2

y=6

x+6=13

x=13-6

x=7

7+6=13

7-6=1

x+y=19

2x-y=11

x=19-y

2(19-y)-y=11

38-2y-y=11

38-3y=11

-3y=11-38

-3y=-27

3y=27

y=27/3

y=9

x+9=19

x=19-9

x=10

10+9=19

2.10-9=11