PRMO 2017 question 19

“If 1,2,3 are roots of 

x4+ax2+bx=cx^4 + a x^2 + b x = c, find cc."

Answer: 36
Solution: simply put 1,2,3 so you get 3 equations in 3 vars and solve for c.

A simpler solution:
By Vieta's formulas
Sum of roots = 0, so 4th root = -6
Product of roots = -c = -36 => c = 36

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