Question

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Answer 1

a) x - 1 = y --> x = y + 1

x + y = 3

y + 1 + y = 3

2y + 1 = 3

2y = 2

y = 1

x = 1 + 2

x = 2

b) x^2 + x + 1 = 1

x^2 = 1 --> x = ±1

daca x = -1

x^2 + x + 1 = 1

1 -1 + 1 = 1

0 + 1 = 1

1 = 1 --> adevarat

daca x = 1

x^2 + x + 1 = 1

1 + 1 + 1 = 1

3 = 1 --> fals

deci x = -1, y = 1