Решение 

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Проверка 

> solve(`<=`(log[`+`(5, `-`(x))](`+`(`*`(`^`(x, 2)), `-`(`*`(14, `*`(x))), 49)), `+`(`*`(2, `*`(log[`+`(5, `-`(x))](`+`(`*`(8, `*`(x)), `-`(`*`(`^`(x, 2))), `-`(7))))), `-`(2))))
 

RealRange(3, Open(4)) (41.2.1)