A quadratic polynomial, whose zeros are - 3 and 4, is
- 3 and 4 are the zeroes of the polynomial p(x) = ax2 + bx + c
∴ sum of the zeroes = - (coefficient of x) ÷ coefficient of x2
- 3 + 4 = - b/a
1 = - b/a
b = - 1 and a = 1
Product of the zeroes = constant term ÷ coefficient of x2
c = (- 3)/4
⇒ c = 12
Putting the values of a, b and c in the polynomial p(x) = ax2 + bx + c
∴ The polynomial is x2 - x - 12
= x2/2 - x/2 - 6 (dividing by any constant will not change the polynomial)
OR
The equation of a quadratic polynomial is given by x2 - (sum of the zeroes) x + (product of the zeroes) where,
Sum of the zeroes = - (coefficient of x) ÷ coefficient of x2 and
Product of the zeroes = constant term ÷ coefficient of x2
∴ Sum of the zeroes = - 3 + 4 = 1
and
product of the zeroes = (- 3)4 = - 12
⇒ x2 - (1)x = (- 12)
= x2 - x - 12
= x2/2 - x/2 - 6
(dividing by any constant will not change the polynomial)