Question 331590
<font face="Garamond" size="+2">


Let *[tex \Large u\ =\ \sqrt{y}]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ u^2\ +\ 6u\ -\ 16\ =\ 0]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ (u\ -\ 2)(u\ +\ 8)\ =\ 0]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ u\ =\ 2\ \ \Rightarrow\ \ y\ =\ 4]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ u\ =\ -8\ \ \Rightarrow\ \ y\ \ ] DNE.


There is no value of *[tex \Large y] such that *[tex \Large \sqrt{y}\ =\ -8]


Solution set is *[tex \Large \{4\}]


John
*[tex \LARGE e^{i\pi} + 1 = 0]
My calculator said it, I believe it, that settles it
<img src="http://c0rk.blogs.com/gr0undzer0/darwin-fish.jpg">
</font>