Question

sum and product of the zeros in polynomial are
A. b/a and c/a
B. - b/a and - c/a
C. - b/a and c/a
D. None of the above​

Answer 1

f(x) = axn + bxn-1 + cxn-2 + ... + z

Then:

Adding the roots gives −b/a

Multiplying the roots gives:

z/a (for even degree polynomials like quadratics)

−z/a (for odd degree polynomials like cubics)

Which can sometimes help us solve things.

How does this magic work? Let's find out ...

Factors

We can take a polynomial, such as:

f(x) = axn + bxn-1 + cxn-2 + ... + z

And then factor it like this:

f(x) = a(x−p)(x−q)(x−r)...

Then p, q, r, etc are the roots (where the polynomial equals zero)