0,6 ^ 1/8 = ( 3/5 ) ^ 1/8
5 ^ 1/4 = 5 ^ 2/8
15 ^ 7/8 = ( 3 ^ 7/8 ) * ( 5 ^ 7/8 )
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( 3 ^ 1/8 ) * ( 5 ^ 2/8 ) * ( 5 ^ 7/8 ) * ( 3 ^ 7/8 ) = ( 3 ^ 8/8 ) * ( 5 ^ 9/8 ) =
= 3 * ( 5 ^ 9/8 )
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( 5 ^ 9/8 ) : ( 5 ^ 1/8 ) = 5 ^ 8/8 = 5
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3 * 5 = 15
ОТВЕТ 15