Question

solve each equation. state the number and type of roots:
PROBLEM:
x^(3)+6x+20=0
answer pwease and explanation... ^__^

Answer 1

using factor theorem
let x = -2
them f(-2) = )-2(^3 - 12 + 20 = 0
so x = -2 is one root and x + 2 is a factor

Answer 2

ohhhh okiii, thanks :D

Answer 3

BUT,BUT why did u use 2?

Answer 4

just by observation - its not always possible of course

Answer 5

now divide x^(3)+6x+20 by x + 2
gives
x^2 - 2x + 10
- solve this to get the other roots

Answer 6

ahhh do i really need to solve them......tooo much work >.<"

Answer 7

x = -(-2) +- sqrt(4 - 4 *1 *10) / 2
- oh right - no. and type of roots

there are 3 roots one real - thats the 2 and 2 complex roots as u can see from the above
the sqrt is of a negative number

Answer 8

ahhhh i get it now, thank you so much ^^

Answer 9

perhaps theres a simpler way of doing this which i dont know about

you r welcome

Answer 10

yea i think there is, cause my alg teacher taught us 2 ways, the long an short, in which i tottly forgot.... ^^" uhhhg meh, im so irresponsible, but thanks dude~