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