Question

if x^2 + 3x + 5 is a factor of x^4 + ax^2 + b, what is a + b

Answer 1

Answer:

x^2 + 3x + 5 = x^4 + ax^2 + b,

(1 - a) x^2 - x^4 + 3x + (5 +b) = 0

(1 - a) x^2 = 0 , (5 +b) = 0

1 - a = 0 , b = -5

a = -1

a + b = -1 -5 = -6