Maths Olympiad Prep

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Algebra Difficulty 4.9 AIME Find the answer

A triple of integers (a,b,c)(a, b, c) satisfies a+bc=2017a+b c=2017 and b+ca=8b+c a=8. Find all possible values of cc.

A number or a short expression. Spacing and $ signs are ignored.

Solution

Add and subtract the two equations to find (b+a)(c+1)=8+2017(b+a)(c+1)=8+2017 and (ba)(c1)=20178(b-a)(c-1)=2017-8. We see that cc is even and then that every integer cc with c+12025,c12009c+1|2025, c-1| 2009 works. We factor and solve. The full solutions are (2017,8,0),(667,1342,2),(59,346,6),(31,256,8)(2017,8,0),(-667,1342,2),(-59,-346,-6),(-31,256,8).

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