Find a polynomial function of degree 3 with real coeffcients that has the given zeros. -1, 2, -5

Answer 1

The Polynomial (P) has Zeroes at -1,2,-5.

Therefore P(-1) = 0, thus (x- (-1)) is a factor i.e. (x+1).

Similarly (x-2) & (x+5) are factors.

P(x) = (x+1)(x-2)(x+5)

Hope this helps,

Pradip

Answer 2

(x+1)(x-2)(x+5)

(x^2-x-2)(x+5)

x^3 - x^2 -2x

5x^2 -5x - 10

x^3 + 4x^2 - 7x - 10