V ( X^2 + 16) = V ( 2X - 1)^2
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X^2 + 16 = 4X^2 - 4X + 1
4X^2 - X^2 - 4X + 1 - 16 = 0
3X^2 - 4X - 15 = 0
D = 16 + 180 = 196 ; V D = 14
X1 = ( 4 + 14 ) : 6 = 18/6 = 3
X2 = ( - 10) : 6 = ( - 10/6) = ( - 1 2/3 )
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2Х - 1 > 0 ---> 2X > 1 ---> X > 1/2
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Ответ Х = 3