Question

What is the sum of the roots of the polynomial shown below?

F(x)=3x^3+12x^2+3x-18

Answer 1

sum of roots = -b/a

Note that :
F(x) = ax^3 + bx^2 + cx + d

Answer 2

try to factor (x-1)
because x=1 is one of roots
(f(1)=0 if you check)

Answer 3

the sum of the roots are -4

Answer 4

So you want to find your values of a and b by matching it up :)
\[F(x) = ax^3 + bx^2 + cx + d \]
\[F(x)= 3x^3 + 12x^2 + 3x - 18\]

Answer 5

you're close :) just missing a negative sign!

Answer 6

If you look at the above, we get:
a = 3
b = 12

Sum of roots = \[-b/a\]
Therefore
sum of roots = -12 / 3 = -4

Answer 7

he/she did not miss -

Answer 8

-_- oops, you wrote -4
You're correct! :)

Answer 9

she lol

Answer 10

another observation is to write it
\[f(x)=3(x-1)(x+3)(x+2)\]