Question

If the equation x^4-4x^3+ax^2+bx+1=0 has 4 positive roots find a and b

Answer 1

Answer:

Step-by-step explanation:

In this particular case, we can have a simpler approach.

By observation, it clear that the first, second and fifth terms are the terms of the expansion of (x−1)4=0, which has all the four roots equal to 1.

(x−1)4=0⇒x4−4x3+6x2−4x+1=0.

⇒a=6 and b=−4.

⇒a−b=10.