Question

If 1,m and k are the roots of the cubic polynomial whose sum is 5 and sum of product of roots taken two at a time is 8, then value of (m-k) is,

• A. 0
• B. 1
• C. 2
• D. 3

Answer 1

The correct option is A

0

Adding 1+m+k we get 5, and taking the sum of product of roots two at a time: m+k+mk = 8, m+k=4 and mk=4

Only number 2 is satisfied, so m-k=0.