Disproving Statement: No Natural Numbers Satisfy y^5 + 1 = (x^7-1)/(x-1)

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The discussion revolves around proving that there are no natural numbers x and y satisfying the equation y^5 + 1 = (x^7 - 1)/(x - 1). Participants simplify the equation and analyze the implications of prime factors and coprimality. They conclude that if x and c (derived from the equation) are both fifth powers, contradictions arise regarding their coprimality. Ultimately, they establish that no positive integer values for e exist that satisfy the equation, leading to the conclusion that the original statement is indeed disproven. The critical insight is that the factors involved cannot simultaneously satisfy the conditions required for both being fifth powers.
  • #31
Faiq said:
I don't think its necessary for both to be a fifth power consider this
y5 = (ab)5 = a5.b5
C = a5.b
x = b4
y5 = cx = (a5.b)(b4) = a5.b5 =(ab)5
But then C and x wouldn't be coprime they would have common factor b.
 
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  • #32
Oh yeah right thanks
 
  • #33
Btw you are right about case 1 and 3 we just omitted them because they kind of intuitively obvious that they lead to contradiction.
 
  • #34
Thank you very much for the help
 
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