1.

If the sum of zeroes of a quadratic polynomial 3x^2 - kx + 6 is 3 , find the value of k *

Answer»

\large{\underline{\bf{\green{Given:-}}}}

  • ✦ SUM of zeroes = 3
  • ✦ p(x) = 3x² - kx + 6

\large{\underline{\bf{\green{To\:Find:-}}}}

\huge{\underline{\bf{\purple{Solution:-}}}}

p(x) = 3x² - kx + 6

  • a = 3
  • b = -k
  • c = 6

sum of zeroes = - b/a

➝ 3 = -(-k)/3

➝ 3 = k/3

➝ k = 3×3

➝ k = 9

So,

Value of k is 9.

p(x) = 3x² - kx + 6

➝ 3x² - 9x + 6

➝ 3x² - 3x - 6x +6

➝ 3x(x -1) -6(x -1)

➝ (3x-6) (x -1)

➝ x = 2 or x = 1

Verification :-

sum of zeroes = - b/a

➝ 2 +1 = -(-9)/3

➝ 3 = 3

product of zeroes = c/a

➝ 2×1 = 6/3

➝ 2 = 2

LHS = RHS

HENCE , Verified

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