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

1.	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» (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

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»

(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