Math miscellaneousHard
Question
If x2 - 3x + 1 = 0, then value of expression x9 + x7 + x-9 + x-7 is equal to :-
Options
A.4
B.2207
C.6621
D.4414
Solution
x2 - 3x + 1 = 0
x +
= 3 ; x2 + 
= 7; x4 + 
= 47
x9 + x7 + x-9 + x-7 x8 + x8 +
= 2207
x8
+ x-8 
= 3 × 2207 = 6621
x +
= 3 ; x2 + = 7; x4 + = 47x9 + x7 + x-9 + x-7 x8 + x8 +
= 2207x8
+ x-8 = 3 × 2207 = 6621Create a free account to view solution
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