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 factorization.
- 23, - 9
Sum of the zeroes = - 2√3
Product of the zeroes = - 9
P(x) = x2 - (sum of the zeroes) + (product of the zeroes)
= x2 - 2√3x 9
By splitting the middle term
x2 - 2√3x - 9 = 0
x2 - (- √3x + 3√3x) - 9 = 0
x2 + √3x - 3√3x - 9 = 0
x(x + √3) - 3√3(x + √3) = 0
(x + √3)(x - 3√3) = 0
⇒ x = - √3, 3√3