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

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

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

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

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

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

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

zepdrix
 one year 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.
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