Question

Решите уравнение x/(x + 4) = 3/(x - 1)​

Answer 1

Объяснение:

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Answer 2

по правилу пропорции получим

$\frac{x}{x + 4} = \frac{3}{x - 1} \\ 3(x + 4) = x(x - 1) \\ 3x + 12 = x {}^{2} - x \\ 3x + 12 - x {}^{2} + x = 0 \\ 4x + 12 - x {}^{2} = 0 \\ - x {}^{2} + 4x + 12 = 0 \\ d = 4 {}^{2} - 4 \times ( - 1) \times 12 = 16 + 48 = 64 = 8 {}^{2} \\ x_{1} = \frac{ - 4 - 8}{ - 2} = \frac{ - 12}{ - 2} = 6 \\ x_{2} = \frac{ - 4 + 8}{ - 2} = \frac{4}{ -2 } = - 2$