quadratic

Let f(x)=x2+bx+c,where b,c\in R . If f(x) is a factor of both x4+6x2+25 and 3x4+4x2+28x+5 , then the least value of f(x) is

7 Answers

1
chinmay ·

anyone??

62
Lokesh Verma ·

(x2+5)2-4x2

now try

1
chinmay ·

one more hint pls!!

62
Lokesh Verma ·

(x2+5)2-4x2 = (x2+5-2x)(x2+5+2x)

both cannot be factorized further

check which of the two is a factor of the other polynomial!

341
Hari Shankar ·

Another line of thought:

Let P(x) = x4+6x2+25 and Q(x) = 3x4+4x2+28x+5

If f(x) divides both P(x) and Q(x),

it must divide 3P(x) - Q(x) = 14(x2+2x+5)

So, f(x)≡x2+2x+5 = (x+1)2+4 ≥4

1
skygirl ·

simply great!

11
Subash ·

prophet sirs posts can be automatically pinked

every post shows so much proficiency :)

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