A community for students.
Here's the question you clicked on:
 0 viewing
DeadShot
 2 years ago
Which of the following is a polynomial with roots  square root of 5, square root of 5, and 3 ? x3  2x2  3x + 6, x3 + 2x2  3x  6, x3  3x2  5x + 15, or x3 + 3x2  5x  15?
DeadShot
 2 years ago
Which of the following is a polynomial with roots  square root of 5, square root of 5, and 3 ? x3  2x2  3x + 6, x3 + 2x2  3x  6, x3  3x2  5x + 15, or x3 + 3x2  5x  15?

This Question is Closed

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3If you have roots of: a, b, and c your polynomial has the form: (x  a)(x  b)(x  c) = 0 Substitute a, b, and c for the given roots and multiply the expression out on the left side.

DeadShot
 2 years ago
Best ResponseYou've already chosen the best response.0x^3 2.25x^2+2.25x^23x22.25x+2.25x3x15

DeadShot
 2 years ago
Best ResponseYou've already chosen the best response.0simplified, it's x^33x^23x15, right?

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3You wouldn't even have to ask that last question because you have 4 choices and this choice is not even listed among them. Here's a hint on how to expand that expression I gave you: (x  a)(x  b)(x  c) = 0 [(x  a)(x  b)](x  c) = 0 [x^2  (a + b)x + ab](x  c) = 0 [x^2  (a + b)x + ab]x  [x^2  (a + b)x + ab]c = 0

DeadShot
 2 years ago
Best ResponseYou've already chosen the best response.0[x^2(2.25+2.25)x + (2.25)*2.25]x[x^2(2.25+2.25)x + (2.25)*2.25]3=0

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3Where are you getting +2.25 from? Neither has anything to do with sqrt(5).

DeadShot
 2 years ago
Best ResponseYou've already chosen the best response.0sqrt(5) is approx 2.25

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3You don't want to be working with approximations here.

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3I would suggest evaluating the following first: [x  sqrt(5)][x + sqrt(5)] That correspond to the leftmost factors. Get that down to a trinomial.

DeadShot
 2 years ago
Best ResponseYou've already chosen the best response.0(x^25) (x3)=x^3  3x^2  5x + 15

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3The third root is "3", so you have: [x  (3)] or (x + 3) for that third factor. I think that's where you having your trouble. When you subtract a negative, it's like adding a positive.

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3So, taking up from where you were writing: (x^2  5)(x + 3) = 0 And then expand that. You are very close to your answer now.

DeadShot
 2 years ago
Best ResponseYou've already chosen the best response.0so, it's x^3+3x^25x15?

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3Yes! Excellent! Just remember about subtracting negatives and you will be ok.

DeadShot
 2 years ago
Best ResponseYou've already chosen the best response.0Okay, Thanks for the help!

tcarroll010
 2 years ago
Best ResponseYou've already chosen the best response.3You're welcome! Good luck to you in all of your studies and thx for the recognition! @DeadShot

malice
 6 months ago
Best ResponseYou've already chosen the best response.1x3 + 3x2  5x  15 is not the correct answer (just took the test)

malice
 one month ago
Best ResponseYou've already chosen the best response.1I am not incorrect. I took and worked on the problem that you were referring to, and I got x3 + 3x2  5x  15 wrong. I take FLVS, so perhaps it was the computer grading system that was incorrect. Besides, this is a graded lesson. It would be extremely mean of me to INTENTIONALLY say inaccurate information.

malice
 one month ago
Best ResponseYou've already chosen the best response.1Well I am practically done with the class now lol...I am mostly working on the module 10. It's like trig based. ^.^ I have my eoc next week, so I have been mega working XDD
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.