If one of the zeroes of cubic polynomial X3 ax2 bx c is -1 then the pr...
Explanation:
Let the zeroes of the polynomial be -1, α and β.
According to the factor theorem, a polynomial with zeroes α and β can be written as:
x2 + (α + β)x + αβ
As the polynomial has -1 as one of its zeroes, it can be written as:
x + 1
Now, equating the two expressions for the polynomial, we get:
x + 1 = x2 + (α + β)x + αβ
Comparing the coefficients of x2, x and the constant term, we get:
α + β = 0
αβ = -1
Now, we need to find the product of the other two zeroes α and β.
Solution:
From the equation α + β = 0, we get:
β = -α
Substituting this in the equation αβ = -1, we get:
α(-α) = -1
-α2 = -1
α2 = 1
α = 1 or α = -1
Since we already know that one of the zeroes is -1, the other two zeroes can be:
α = 1 and β = -1
or
α = -1 and β = 1
Therefore, the product of the other two zeroes is:
αβ = (1)(-1) = -1
or
αβ = (-1)(1) = -1
Hence, the product of the other two zeroes of the cubic polynomial is -1.