A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 one year ago
Using the completingthesquare method, rewrite f(x) = x2 + 4x − 1 in vertex form
anonymous
 one year ago
Using the completingthesquare method, rewrite f(x) = x2 + 4x − 1 in vertex form

This Question is Closed

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Group the terms like this \[f(x)=(x^2+4x)1\] Take the coefficient of x, divide it by 2 and square it. What's \(\left( \frac{ 4 }{ 2 } \right)^2\) ?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Right, so add 4 inside the parentheses. This means you also have to subtract 4 outside, so the equation doesn't change. \[f(x)=(x^2+4x+4)14\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Now factor the part in parentheses, and combine like terms on the outside

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so would it be f(x)=(x^2+4x+4)5

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yes, but you also have to factor x² + 4x + 4

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh I got it. But can you help me with a few others?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Using the completingthesquare method, find the vertex of the function f(x) = –2x2 + 12x + 5 and indicate whether it is a minimum or a maximum and at what point.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0\(f(x)=2x^2+12x+5\) Group it again \(f(x)=(2x^2+12x)+5\) This time, because you have 2 in front of x², you have to factor it out. Can you do that?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0would it be f(x)=2(x^2+12x)+5

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0no, you have to divide 12 by 2 as well because it's also in parentheses

anonymous
 one year ago
Best ResponseYou've already chosen the best response.012/(2)= 6 So you have \[f(x)=2(x^26x)+5\] Now take the coefficient of x, that's 6. Divide it by 2, the square the result like we did above

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay so would it be minimum or maximum?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0the number in front of x² is negative, so it's a maximum

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay so whats the point? (3,5)?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0You have to complete the square to find the point

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0If you don't want to do it that way, use \[x=\frac{ b }{ 2a }\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay I just reset my exam so now I have different questions
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.