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If α, β are the zeroes of the polynomial f(x) = x^2 – 5x + k such that α – β = 1, find the value of k = ?

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If α, β are the zeroes of the polynomial f(x) = x2 – 5x + k such that α – β = 1, find the value of k = ?

If α and β are the zeroes of the polynomial f(x) = x2 – 5x + k such that α – β = 1, find the value of k.

Sum
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Solution

By using the relationship between the zeroes of the quadratic polynomial.

We have  

Sum of zeroes = `(-("Coefficient of"  x))/("Coefficient of"  x^2)` and Product of zeroes = `("Constant term")/("Coefficient of "x^2)`   

∴ `α + β = (-(-5))/1` and `αβ = k/1`

⇒ α + β = 5 and αβ = `k/1`

Solving α – β = 1 and α + β = 5, we will get 

α = 3 and β = 2 

Substituting these values in αβ = `k/1`, we will get 

k = 6

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Chapter 2: Polynomials - EXERCISE 2C [Page 66]

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R.S. Aggarwal Mathematics [English] Class 10
Chapter 2 Polynomials
EXERCISE 2C | Q 21. | Page 66

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