Question

What is the sum of the roots of the polynomialshown below?
f(x)=3x^3+12x^2+3x-18

Answer 1

factor a 3 and u can "see" 1 root

Answer 2

Hint: The sum of the roots of the polynomial

\[a_nx^n+a_{n-1}x^{n-1}+\cdots+a_1x+a_0\]

is \[-\frac{a_{n-1}}{a_n}\]

See link below for more info

http://www.slideshare.net/kliegey524/polynomials-sum-and-product-of-the-roots

Answer 3

Didn't know that formula, I checked, -6,1,1. Thanks.

Answer 4

It turns out that the roots are -3,-2, and 1. Add them up to get -4.


We can see that \[a_{n-1}=a_{2}=12\] and \[a_n=a_3=3\], so the sum of the roots is \[-\frac{a_{n-1}}{a_n}=-\frac{12}{3}=-4\]

Answer 5

Have to go to polynomial classes, lol

Answer 6

lol yea