Question

If $\frac{1}{4 - 3i}$is a root of ax² + bx + 1 = 0, where a, b are real, then-

• A. a = 25, b = –8
• B. a = 25, b = 8
• C. a = 5, b = 4
• D. None of these

Answer 1

Answer: (A)

a = 25, b = –8

Answer 2

If α =$\frac{1}{4 - 3i}$, β =$\frac{1}{4 + 3i}$⇒ αβ= $\frac{1}{a}$=$\frac{1}{25}$⇒a= 25

α + β = $\frac{- b}{a}$= $\frac{8}{25}$⇒ b = –8