AP EAMCET · Maths · Complex Number
If \(2+4 i\) is one of the roots of \(x^2+b x+c=0\) with \(b, c \in \mathbf{R}\) then \((b, c)=\)
- A \((4,-20)\)
- B \((4,20)\)
- C \((-4,-20)
- D (-4,20)\)
Answer & Solution
Correct Answer
(D) (-4,20)\)
Step-by-step Solution
Detailed explanation
It is given that \(2+4 i\) is one of the roots of \(x^2+b x+c=0\) with \(b, c \in \mathbf{R}\), so other root will be \(2-4 i\). Now, the sum of roots \(=-b\) \(\Rightarrow \quad(2+4 i)+(2-4 i)=-b \Rightarrow b=-4\) and the product of roots \(=c\)…
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