Question

a){×-y=3 adição
2×+y=9​

Answer 1

a) {x - y = 3

{2x + y = 9

3x = 12

x = 12

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3

x = 4

2x + y = 9

2 . 4 + y = 9

8 + y = 9

y = 9 - 8

y = 1

x - y = 3

4 - 1 = 3

3 = 3

2x + y = 9

2 . 4 + 1 = 9

8 + 1 = 9

9 = 9

S = {(4 ; 1)}