Question

Find a third-degree polynomial equation with rational coefficients that has roots -4 and 6+i.

When I solved this, I got the answer x^3-8x^2-13x+140. This is not one of the answers. Can someone tell me what I did wrong?

Answer 1

*fanning me before I even help? haha ^_^

Answer 2

You helped me on a previous problem yesterday and I forgot to fan you because I couldn't find you! Haha

Answer 3

oh did i? lol

Answer 4

I know you started by doing (x+4)(x-(6+i))(x-(6-1))

Answer 5

And then once you get passed all of that... you get (x+4)(x^2-12x+35)

Answer 6

jk, ur right

Answer 7

What am I right about? Lol

Answer 8

give me a sec..

Answer 9

Okay! Thank you

Answer 10

"has roots -4 and 6+i."
doesn't this mean these are the only possible roots?

Answer 11

I'll send you the possible answer choices

Answer 12

x^3-8x-11x+148=0
x^3-8x^2-12x+37=0
x^3-12x+37=0
x^2-11x=0

Answer 13

Oops, the last one is x^3-8x^2-11x=0

Answer 14

I got what you got... O.o

Answer 15

Hmmm...

Answer 16

I don't know what I did wrong...

Answer 17

when you foil your complex conjugates you shouldn't have a middle term with an x

Answer 18

@jdoe0001

Answer 19

well yyou would get
(x+4)(x^2-12x+37)
then foil that

Answer 20

remember -I^2=+1

Answer 21

you get
x^3-8x^2-11x+148

Answer 22

That's what I got too! Okay. Thank you!!

Answer 23

no problem. little 1 number mistakes can mess with you.

Answer 24

Yes they can... I figured it was something like that