10^x = ⁴√1000
10^x = 1000 ^ 1/4
10^x = 10 ^ 3/4
x = 3/4
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5 ^ x = 1 / ( ∛ 25 )
5 ^ x = 1 / ( 5 ^ 2/3 )
5 ^ x = 5 ^ ( - 2/3 )
x = - 2/3
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0,3 ^ x = 1000 / 27
0,3 ^ x = ( 27/1000 ) ^ - 1
0,3 ^ x = 0,027 ^ - 1
0,3 ^ x = 0,3 ^ - 3
x = - 3
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( 4/5 ) ^ x = 25/16
( 4/5 ) ^ x = ( 16/25 ) ^ - 1
( 4/5 ) ^ x = ( 4/5 ) ^ - 2
x = - 2