18A^5 - 6A^4B = 6A^3 * ( 3A^2 - AB )
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[ 6A^3 * ( 3A^2 - AB ) ] : 6A^3 = 3A^2 - AB
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3A^2 - AB = A * ( 3A - B )
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A = 5 ; B = - 10
A * ( 3A - B )
5 * ( 15 + 10 ) = 5 * 25 = 125
ОТВЕТ 125