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Further Arithmetic Integers (Posted on 2006-06-27) Difficulty: 3 of 5
Consider three positive integers x < y < z in arithmetic sequence, and determine all possible solutions of: x4 + y4 = z4 - 64

See The Solution Submitted by K Sengupta    
Rating: 3.3333 (3 votes)

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mathematica solution (spoiler) | Comment 5 of 10 |
gotta love mathematica's reduce function

Fnc[x_,y_]:=15*y^4-32*x*y^3+24*x^2*y^2-8*x^3*y-64;
Reduce[{Fnc[x,y]==0,y>x,x>0},{x,y},Integers]

how I got the Fnc function is I used z=y+(y-x)=2y-x and set all equal to zero

in a matter of miliseconds it pops out

x=1,y=2
x=7,y=8

  Posted by Daniel on 2006-06-28 06:03:32
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