Question

9. If the sum of zeroes of the quadratic polynomial 3x2 - kx
+ 6 is 3, then find the value of k.​

Answer 1

Answer :

k = 9

Step-by-step explanation :

➤ Quadratic Polynomials :

  ✯ It is a polynomial of degree 2

  ✯ General form :

            ax² + bx + c  = 0

  ✯ Determinant, D = b² - 4ac

  ✯ Based on the value of Determinant, we can define the nature of roots.

          D > 0 ; real and unequal roots

          D = 0 ; real and equal roots

          D < 0 ; no real roots i.e., imaginary

  ✯ Relationship between zeroes and coefficients :

            ✩ Sum of zeroes = -b/a

            ✩ Product of zeroes = c/a

________________________________

Given polynomial,

3x² - kx + 6

It is of the form ax² + bx + c

a = 3 , b = -k , c = 6

Sum of the zeroes = 3

        -b/a = 3

        -(-k)/3 = 3

         k/3 = 3

         k = 3 ×3

         k = 9

The value of k is 9