Question

Доведіть тотожність:
а) 2(а – b – 1) – (a + b – 1) – (a – b + 1) = –2(b + 1);

б) 1 – х – (1 – (1 – (1 – х))) = 0.

Answer 1

а) 2(а – b – 1) – (a + b – 1) – (a – b + 1) = –2(b + 1)

2а - 2b - 2 - a - b + 1 - a + b - 1 = -2b - 2

-2b - 2 = -2b - 2

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б) 1 – х – (1 – (1 – (1 – х))) = 0

1 - x - (1 – (1 – 1 + x) = 0

1 - x - (1 - 1 + 1 - x) = 0

1 - x - (1 - x) = 0

1 - x - 1 + x = 0

0 = 0

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