Всякие.Серебро,бронза,золото.
X^2 = A ; A > 0
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9A^2 - 82A + 9 = 0
D = 6724 - 324 = 6400 ; √ D = 80
A1 = ( 82 + 80 ) : 18 = 9
A2 = ( 82 - 80 ) : 18 = 2/18 = 1/9
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X^2 = 9
X1 = 3
X2 = - 3
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X^2 = 1/9
X3 = 1/3
X4 = - 1/3