# If a,b,x,y are real numbers and ax+by=3, ax^2+by^2=7, ax^3+by^3=16 and ax^4+by^4=42 then find ax^5+by^5

It is a standard question of recurrence relations. In such questions, always try to relate T(n-1), T(n) and T(n+1) using simple algebra.

Here is your solution

Thanks and regards.

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