Question

Решите пожалуйста номер 4

Answer 1

$\frac{(x + 1) {}^{2} }{6} + \frac{(x - 1) {}^{2} }{12} - \frac{x {}^{2} - 1 }{4} = 1$

умножим обе части на 12

$\frac{(x + 1) {}^{2} \times 12 }{6} + \frac{(x - 1) {}^{2} \times 12 }{12} - \frac{(x {}^{2} - 1) \times 12 }{4} = 1 \times 12 \\ 2 (x + 1) {}^{2} + (x - 1) {}^{2}- 3 (x {}^{2} - 1) = 12 \\ 2 (x {}^{2} + 2x + 1) + (x {}^{2} - 2x + 1) - 3 (x {}^{2} - 1) = 12 \\ 2 {x}^{2} + 4x + 2 + x {}^{2} - 2x + 1 - 3x {}^{2} + 3 = 12 \\ 2x = 6 \\ x = 3$

Ответ:3

Answer 2

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