91Ó°ÊÓ

Problem: Solve: \(x^{2}+2=36\) Incorrect Answer: \(x^{2}+2=36\) \(\sqrt{x^{2}}+2=\sqrt{36}\) or \(\sqrt{x^{2}}+2=-\sqrt{36}\) \(x+2=6\) or \(x+2=-6\) \(\frac{-2-2}{x+0=4}\) or \(\quad \frac{-2}{x+0=-8}\) \(x=4 \quad\) or \(\quad x=-8\)

Find the amount of yen equal to 1 U.S. dollar (the exchange rate). Round to the nearest tenth. The Insight first went on sale in Japan last month, where it sells for \(1.89\) million yen \((\$ 19,260)\). (Source: http:// latimesblogs.latimes.com, March 2009)

Explain why \(\sqrt{-2}\) is not a real number.