4 √ 0,25 + √ 49 = 4 * 0,5 + 7 = 2 + 7 = 9
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√ ( 25 ^2 ) - ( 24 ^2 ) = √ ( 25 - 24 )*( 25 + 24 ) = √ 1 * 49 = 7
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√ 24 - 4 √ 6 + √ 54 = 2 √ 6 - 4 √ 6 + 3 √ 6 = √ 6
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2K - ( √ K - √ M)*( √ K + √ M ) = 2K - ( K - M ) = 2K - K + M = K + M