√ ( Х - 5) + ⁴ √ ( Х - 5 ) = 30
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⁴ √ ( Х - 5 ) = A
√ ( X - 5) = A^2
A > 0
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A + A^2 = 30
A^2 + A - 30 = 0
D = 1 + 120 = 121 ; √ D = 11
A1 = ( - 1 + 11 ) : 2 = 5
A2 = ( - 12 ) : 2 = ( - 6) ; < 0
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√ ( X - 5 ) = 5^2
√ ( X - 5) = 25
( √ X - 5)^2 = 25^2
X - 5 = 625
X = 625 + 5
X = 630
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Ответ Х = 630
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Проверка
√ 625 + ⁴ √ 625 = 30
25 + √ 25 = 30
25 + 5 = 30
30 = 30