For each of the following, find a quadratic polynomial whose sum and product respectively of
the zeroes are as given. Also find the zeroes of these polynomials by factorisation.
(1)-8/3,4/3 (2) 21/8,5/16 (3) -2√3,-9 (4) -3/2√5,-1/2
with steps completely
Answers
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Find the quadratic polynomial sum and product of whose zeroes are as given also find the zeroes if these polynomial by factorisation. (1) -2√3 ,-9
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EXPLANATION.
Quadratic polynomial whose sum and product are given,
As we know that,
Quadratic Polynomial ⇒ x² - (α + β)x + αβ.
Sum of zeroes of quadratic Equation,
⇒ α + β = -b/a.
⇒ α + β = -2√3.
Product of zeroes of quadratic Equation,
⇒ αβ = c/a.
⇒ αβ = -9.
Put the value in equation, we get.
⇒ x² - (α + β)x + αβ.
⇒ x² - (-2√3)x + (-9).
⇒ x² + 2√3x - 9.
⇒ x² + 2√3x - 9.
As we know that,
⇒ D = b² - 4ac.
⇒ D = (2√3)² - 4(1)(-9).
⇒ D = 12 + 36.
⇒ D = 48.
⇒ D = 4√3.
⇒ x = -b ± √D/2a.
⇒ x = -2√3 ± √4√3/2.
⇒ x = -2√3 - √4√3/3 and x = -2√3 + √4√3/3.
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MORE INFORMATION.
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Conjugate Roots,
If,
D < 0 ⇒ One Roots = α + iβ other Roots = α - iβ.
D > 0 ⇒ One Roots = α + √β other Roots = α - √β.
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