Polynomials Question Help (1 Viewer)

[kev-kun]

Hi all, just wondering if someone could help me with this question. I don't know why but I just can't get to the answer. Thanks ^^

 

[Kurosaki]

Hi all, just wondering if someone could help me with this question. I don't know why but I just can't get to the answer. Thanks ^^

View attachment 28435

if two are equal, then that means that they are the same. So then let those two be alpha and the last one be beta.
then just apply sum of roots, product of roots, sum of roots two at a time and you'll get to m.

 

[Kurosaki]

Btw is m -9? Just checking

 

[kev-kun]

Btw is m -9? Just checking

Yes m= -9 sorry forgot to say answer. And I did what you said before... but I think I'm doing something wrong.

 

[Kurosaki]

Yes m= -9 sorry forgot to say answer. And I did what you said before... but I think I'm doing something wrong.

let the two equal roots be represented by a, and the other root be b

2a+b=-m (1)
a^2+2ab=15 (2)
a^2b=7 (3)

rearrange the last one to give b=7/a^2

then substitute that into the second one. use polynomial division with (x-1) as a factor. you can do the rest

 

[kev-kun]

OMG =='' I see what I did wrong now. Thanks a bunch.

 

[Kurosaki]

No problem