a = 6^123 + 3^146
U(6^123) = 6
U ( 3^146) = U (3^2) = 9
U ( a) = U ( 6 + 9) = U ( 15) = 5
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a = 2^1 × 2^2 × 2^3 × 2^4 × ...× 2^40
(avem aceeasi baza si adunam exponentii )
a = 2 ^ ( 1 + 2 + 3 + 4 +...+ 40)
(calculam suma cu ajutorul Sumei lui Gauss)
a = 2^( 40 × 41 : 2)
a = 2^(20 × 41)
a = 2^820
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25^x+3 = 125^8
25^x × 25^3 = (5^3)^8
(5^2)^x × (5^2)^4 = 5^24
5^2x × 5^8 = 5^24
5^2x = 5^24 : 5^8
5^2x = 5^16
2x = 16
x = 8
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