va implor acuuuuu.mmm!!!!!

Răspuns:
Explicație pas cu pas:
4.
c = (2^40 + 2^39 + 2^38) : 7 = 2^38*(2^2 + 2 + 1) : 7 = 2^38*7 : 7 = 2^38 = (2^19)^2 patrat perfect
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5.
U(5^129) = 5
U(7^1) = 7
U(7^2) = 9
U(7^3) = 3
U(7^4) = 1
U(7^5) = 7
ultima cifra se repeta din 4 in 4
26 : 4 = 6 rest 2
U(7^29) = 9
U(s) = U(5 + 9) = U(14) = 4
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6.
1010110 = 1*2^6 + 1*2^4 + 1*2^2 + 1*2^1 = 64 + 16 + 4 + 2 = 86