Consider the cubic

MATHEMATICS · Single correct · A Level · Mathematics · Algebra and Functions · Algebra and Functions

Problem

Consider the cubic

f(x)=8x^3+4ax^2+2bx+a

, where

a,b\in\mathbb{R}

. If the sum of the base-

2

logarithms of the roots of the cubic

f(x)=0

5

, then the value of

a

is (1)

-64

(2)

-8

(3)

-128

(4)

-256