A community for students.
Here's the question you clicked on:
 0 viewing

This Question is Closed

stottrupbailey
 2 years ago
Best ResponseYou've already chosen the best response.0\[y=\sqrt(x^2+7x)\]

Prebz
 2 years ago
Best ResponseYou've already chosen the best response.0x(y) = 1/2 (7±sqrt(4 y^2+49))

stottrupbailey
 2 years ago
Best ResponseYou've already chosen the best response.0so far I have it down to \[x^2=y^2+7y \]

stottrupbailey
 2 years ago
Best ResponseYou've already chosen the best response.0I'm just kind of confused

zepdrix
 2 years ago
Best ResponseYou've already chosen the best response.1\[\large y=\sqrt{x^2+7x} \qquad \rightarrow \qquad x=\sqrt{y^2+7y}\]Squaring both sides,\[\large x^2=y^2+7y\]Let's complete the square on y, half of 7, squared, is \(\dfrac{49}{4}\).\[\large x^2+\frac{49}{4}=y^2+7y+\frac{49}{4}\] \[\large x^2+\frac{49}{4}=\left(y+\frac{7}{2}\right)^2\] I think maybe do something like this to deal with the different degrees of y. Does that make sense?

stottrupbailey
 2 years ago
Best ResponseYou've already chosen the best response.0umm kind of... I'm a little lost at the part where you do the 49/4. This is a homework question online and they want a y= something, equation

zepdrix
 2 years ago
Best ResponseYou've already chosen the best response.1Yah there would be a couple more steps to get it there :) ~Taking the square root of both sides,\[\large \pm\sqrt{x^2+\frac{49}{4}}=y+\frac{7}{2}\]

zepdrix
 2 years ago
Best ResponseYou've already chosen the best response.1Confused about the `completing the square` step though?

Prebz
 2 years ago
Best ResponseYou've already chosen the best response.0\[y=(\frac{ 1 }{ 2 } (7±\sqrt{(4 x^2+49)})\]

zepdrix
 2 years ago
Best ResponseYou've already chosen the best response.1\[\large x^2+bx\]To complete the square, we take half of the b term, and square it. That is the term we will want to ADD to complete the square.\[\large \left(\frac{b}{2}\right)^2 \qquad \rightarrow \qquad \frac{b^2}{4}\]So to complete the square we would add this term,\[\large x^2+bx+\frac{b^2}{4}\]And since it's a perfect square, we can write it as,\[\large \left(x+\frac{b}{2}\right)^2\]

zepdrix
 2 years ago
Best ResponseYou've already chosen the best response.1Hmm completing hte square can be a little tricky if you don't remmeber how to do it :( I can't think of the best way to explain it.

stottrupbailey
 2 years ago
Best ResponseYou've already chosen the best response.0the answer prebz gives is the right one, is that what you got zepdrix?

zepdrix
 2 years ago
Best ResponseYou've already chosen the best response.1Yah that's the same :) His just has the 1/2 factored out, so it looks nicer.
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.