问题
计算题
因式分解：
4a（b-a）-b2。
答案
解：原式=4ab-4a2-b2
=-（4a2-4ab+b2）
=-（2a-b）2。
搜题请搜索小程序“爱下问搜题”
因式分解：
4a（b-a）-b2。
解：原式=4ab-4a2-b2
=-（4a2-4ab+b2）
=-（2a-b）2。
阅读下面短文，掌握其大意，然后从各题所给的四个选项（A、B、C、D）中，选出最佳选项，并在答题卡上将该项涂黑。
We recently treated our new-adult son and his girlfriend to a seafood feast, near Cocoa Beach, Florida. Our server, a grandmotherly woman skilled in the art of___36_____, flew around the ___37_____juggling dishes and drinks while treating customers as individuals. She remembered their ____38_____tastes likes and dislikes –all of which she’d learned after only the briefest ____39_____. At the end of the meal, she presented the bill, and then went to____40_____ the growing crowd of other dinners. My husband ___41____with a credit card, added her___42____, and we were off. “Mr. Goldsmith!” our waitress ran out of the dining room waving a receipt at him, “Thank you.” He looked at her as though he didn’t __43_____. We’ve all seen that universal___44___ of confusion—eyebrows drawn together and head cocked to one side “What did you give her?” I asked in a stage whisper, ____45___if he had done something __46___ or made a calculation error. “Wow, Dad,” our son said, ___47___like an awestruck 10 –year-old. “I’ve never seen a waitress ____48____anyone out of the restaurant to say ‘thank you’ for the tip. “She gave us great service. I just thought she deserved a little bump __49_____ what I usually give.” It wasn’t until later, when I accidentally heard our ___50____retelling the story of the ___51___waitress, that I realized she had given my family something___52___ a “thank you”. She showed our son the importance of ___53_____hard work and the rewarding sound of “thank you”. Her show of thanks helped a dad earn a bit more ___54___from a loving son. And it reminded me just why I ___55____this thoughtful, caring man.
|