Question

What polynomial has roots of -4, 2, and 5 ?

a.) x3 - x2 - 22x + 40
b.) x3 + x2 - 22x - 40
c.) x3 + 3x2 - 18x - 40
d.) x3 - 3x2 - 18x + 40

Answer 1

use the factor theorem

f(-4), f(2) and f(5)

I'd try f(-4) is all... if you get any there f(-4) = 0

then that is a possibility, then try f(2) if f(2) = 0 try f(5)

the equation where f(-4) = 0, f(2) = 0 and f(5) = 0 is a solution

Answer 2

If a, b, and c are roots of a polynomial, then the polynomial is
(x - a)(x - b)(x - c) = 0

Answer 3

Replace a, b, and c with -4, 2, and 5 and multiply out the three binomials.

Answer 4

the answer is c?

Answer 5

It's d.

Answer 6

what!!!!!!!!!!

Answer 7

(x - (-4))(x - 2)(x - 5)
= (x + 4)(x - 2)(x - 5)
= (x^2 + 2x - 8)(x - 5)
= x^3 - 3x^2 - 18x + 40

Answer 8

Notice the binomials are
(x - a)(x - b)(x - c)
(x - (-4)) = x + 4
(x - 2) = x - 2
(x - 5) = x - 5