A third degree polynomial with integer coefficients and a leading coefficient of 1 has zeros equal to 6, 5 and 9. When written in standard form, What is the coefficient of the term x?

Verified Answer :

Answer: 129

Step-by-step explanation:

If a polynomial has zeros at x = a, x = b, and x = c, then the polynomial can be expressed as:

\($p(x) = (x - a)(x - b)(x - c)$\)

Given the zeros 6, 5, and 9, the polynomial becomes:

\($p(x) = (x - 6)(x - 5)(x - 9)$\)

We need to expand this product to find the polynomial in standard form

First expand \((x-5)(x-6)\):

\((x-6)(x-5)=x^2-5 x-6 x+30=x^2-11 x+30\)

Now, multiply this result by \((x-9):\)

\((\mathrm{x}^2-11 \mathrm{x}+30\right)(\mathrm{x}-9)=\mathrm{x}^3-9 \mathrm{x}^2-11 \mathrm{x}^2+99 \mathrm{x}+30 \mathrm{x}-270\)

Combine like terms:

\(x^3-20 x^2+129 x-270\)

Therefore, the polynomial in standard form is:

\(p(x)=x^3-20 x^2+129 x-270\)

The coefficient of the x term in this polynomial is 129