If sum of the zeroes = α+β = - 8 and product of zeroes = αβ = 6, then the polynomial whose zeroes are \(\frac{1}{α}\) and \(\frac{1}{β}\) is
(a) \(6x^2+8x+1\)
(b) \(6x^2-8x-1\)
(c) \(6x^2-4x+6\)
(d) \(6x^2-8x+1\)
Answer: Option (a) \(6x^2+8x+1\).
Solution:
Step 1: Use the concept of formation of quadratic polynomial when roots are given
The quadratic polynomial whose roots are \(\alpha\) and \(\beta\) is given by
\(x^2-(\alpha+\beta)x+\alpha\beta\)
So, the polynomial whose roots are \(\frac{1}{\alpha}\) and \(\frac{1}{\beta}\) is
\(x^2-(\frac{1}{\alpha}+\frac{1}{\beta})x+\frac{1}{\alpha} \times\frac{1}{\beta}\)
Step 2: Simplify the coefficient of \(x\) and then use the given values of sum and product of zeroes
\(x^2-(\frac{\alpha+\beta}{\alpha \beta})x+\frac{1}{\alpha \beta}\)
\(x^2-(\frac{-8}{6})x+\frac{1}{6}\) [ ∵ \(\alpha+\beta=-8, \alpha \beta=6\)]
\(\Rightarrow x^2+\frac{8}{6}x+\frac{1}{6}\)
\(\Rightarrow \frac{6x^2+8x+1}{6}\)
\(\Rightarrow \frac{1}{6} \times(6x^2+8x+1)\)
Here, \(\frac{1}{6} \) is the constant.
So, the required polynomial is \(6x^2+8x+1\).
Hence, the correct option is option (a) \(6x^2+8x+1\).