If one of the zeroes of the cubic polynomial x3 + ax2 + bx + c is - 1, then the product of the other two zeroes is


let α, β & γ be the zeroes of the polynomial p(x) = x3 + ax2 + bx + c and

α = - 1 (given)


Zeroes of a polynomial is all the values of x at which the polynomial is equal to zero.


i.e. p (α) = p(- 1) = 0


= (- 1)3 + (- 1)2a + (- 1)b + c = 0


= - 1 + a - b + c = 0


= c = 1 - a + b


Product of zeroes = - (constant term) ÷ coefficient of x3 i.e.


Product of zeroes = - c


αβγ = - c


= βγ = c


= βγ = 1 - a + b

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