Question

If – i + 3 is a root of x² – 6x + k = 0, then the value of k is

(a) 5

(b) √5

(c) √10

(d) 10

Answer 1

(d) 10

α = -i + 3 = 3 – 7 

⇒ The other root is β = 3 + i 

Product of the roots = αβ = (3 – i)(3 + i) = 10 

Product of the roots of x² – 6x + k = 0 is k ⇒ k 

= 10