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If ๐›ผ and ๐›ฝ be the zeroes of the polynomial 2โข๐‘ฅ2 โˆ’7โข๐‘ฅ +๐‘˜ write the value of (๐›ผ + ๐›ฝ + ๐›ผ๐›ฝ). - Mathematics

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Question

If ๐›ผ and ๐›ฝ be the zeroes of the polynomial `2x^2 - 7x + k` write the value of (๐›ผ + ๐›ฝ + ๐›ผ๐›ฝ).

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)` 

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

a = 2, b = −7, and c = k

∴ ∝+ β = `(-b)/c`

= `(-(-7))/2`

= `7/2`

∝β = `c/a`

= `k/2` 

Now, ๐›ผ + ๐›ฝ + ๐›ผ๐›ฝ = `7/2 + k/2`

= `(7 + k)/2`

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Chapter 2: Polynomials - Exercises 3

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R.S. Aggarwal Mathematics [English] Class 10
Chapter 2 Polynomials
Exercises 3 | Q 16

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