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If α, β are the zeroes of the polynomial f(x) = 5x^2 – 7x + 1 then 1/α +1/β = ?

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If α, β are the zeroes of the polynomial f(x) = 5x2 – 7x + 1 then `1/α + 1/β = ?`

If α and β are the zeroes of the polynomial f(x) = 5x2 – 7x + 1, find the value of `(1/α + 1/β)`.

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 = (-(-7))/5` and `αβ = 1/5` 

⇒ `α + β = 7/5` and `αβ = 1/5` 

Now, `1/α + 1/β = (α + β)/(αβ)` 

= `(7/5)/(1/5)` 

= 7

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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 23. | Page 66

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