Вопрос:

Сократите дробь: (25-x^2)/(35-2x-x^2).

Ответ:

\[- x^{2} - 2x + 35 = 0\]

\[x^{2} + 2x - 35 = 0\]

\[x_{1} + x_{2} = - 2;\ \ \ x_{1} \cdot x_{2} = - 35\]

\[x_{1} = 5,\ \ x_{2} = - 7\]

\[- x^{2} - 2x + 35 =\]

\[= - (x - 5)(x + 7) =\]

\[= (5 - x)(x + 7).\]


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