線上遊戲排行榜2013/2014,進擊的巨人線上看,candy crush saga外掛,正妹寫真三圍

http://math1.ck.tp.edu.tw/%E6%9E%97%E4%BF%A1%E5%AE%89/%E5%AD%B8%E8%A1%93%E7%A0%94%E7%A9%B6/%E8%B3%87%E5%84%AA%E7%8F%AD%E8%AA%B2%E7%A8%8B%E8%AC%9B%E7%BE%A9/%E7%AC%AC4%E5%96%AE%E5%85%83%E8%A4%87%E6%95%B8.pdf

如以上連結的練習二

答案我我算出來為-3
不知道答案是否有誤?

題目為以下
(練習2) 若x,y為實數，且x+y=−7,xy=4，求(√x+√y )^2=？ Ans：−11

我先將(√x+√y )^2 展開
=x +2√(xy)+ y = -7+2√(xy) = -7+2*2 =-3

會不會是答案出錯
(練習2) 若x,y為實數，且x+y=−7,xy=4，求(√x-√y )^2=？ Ans：−11
若將題目改成 (√x-√y )^2
=x -2√(xy)+ y = -7-2√(xy) = -7-2*2 =-11 則算出來是-11

This entry passed through the Full-Text RSS service — if this is your content and you're reading it on someone else's site, please read the FAQ at fivefilters.org/content-only/faq.php#publishers. Five Filters recommends: 'You Say What You Like, Because They Like What You Say' - http://www.medialens.org/index.php/alerts/alert-archive/alerts-2013/731-you-say-what-you-like-because-they-like-what-you-say.html