Posted by T.Gracken on September 27, 2002 at 19:47:01:
In Reply to: Re: proof posted by Soroban on September 25, 2002 at 19:19:25:
: : How can I prove there is no integer solution to x^4 + 3x^3 = 1120 ?
: : Thank you.
:
: Look at: x^3(x + 3) = 1120
: x must be a factor of 1120.
: While 1120 has many factors: 1,2,4,5,8,10,16,20,...
: we need to try only the first few and we're done.
: x = 1: 1^3(1 + 3) = 4.... nope!
: x = 2: 2^3(2 + 3) = 40... You get the idea.
very basic but also simple and straightforward! I really like it!!!!