Question

Solve the inequality x 3 – 5x 2 + 8x – 4 > 0

A
(2,∞)
CORRECT ANSWER WRONG ANSWER
B
(1, 2) ∪ (2, ∞)
CORRECT ANSWER WRONG ANSWER
C
(-∞, 1) ∪ (2, ∞)
CORRECT ANSWER WRONG ANSWER
D
(-∞, 1)
CORRECT ANSWER WRONG ANSWER
Solution

Correct option is

(B)

Explanatory Answer :

Let p , q , r are the roots of the cubic equation.

p + q + r = 5

pq+ qr+ pr = 8

pqr = 4

This happens when p = 1 , q = 2 and r = 2

if x is less than 1 , then we get negative value

if x is between 1 and 2 , then we get positive value

if x is greater than 2 , then the value is positive value

hence , the answer is , "(1,2) U (2,)"

B is the correct option