The factors of x4 + x2 + 25 are:
A. (x2 + 3x - 5)(x2 - 3x + 5)
B. (x2 + 3x + 5)(x2 - 3x + 5)
C. (x2 - 3x + 5)(x2 - 3x + 5)
D. (x2 + 3x + 5)(x2 + 3x + 5)
Answer: Option B
Solution (By Examveda Team)
x4 + x2 + 25Check by the option,
(x2 - 3x + 5)(x2 - 3x + 5)
= x4 - 3x3 + 5x2 + 3x3 - 9x2 + 15x + 5x2 - 15x + 25
= x4 + x2 + 25
Other Method
Let the value of x = 1
then, x4 + x2 + 25 = 27
Now check options, and there is only one option that is equal to 27.
(1 + 3 + 5)(1 - 3 + 5) = 9 × 3 = 27
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