题目

定义一种新运算“⊕”：a⊕b=2a﹣ab，比如1⊕（﹣3）=2×1﹣1×（﹣3）=5 （1）求（﹣2）⊕3的值； （2）若（﹣3）⊕x=（x+1）⊕5，求x的值； （3）若x⊕1=2（1⊕y），求代数式2x+4y+1的值． 答案：（1）2 （2）（3） 9Guangzhou （Xinhua news agency）——12 people were killed and 20 injured early yesterday morning when they jumped from a burning train car into the path of an oncoming (即将到来的) goods train in Southern China. When No.247 Wuchang —— Guangzhou passenger train was passing the Dayaoshan Tunnel in Guangdong Province, South China at 00 :17 hours yesterday, a fire caused by passengers' smoking broke out on No.17 car. They wanted to extinguish fire. However, while the train was stopping, some frightened passengers jumped from windows. As a result, 12 passengers were crushed to death and 20 others were injured by an opposite northward passing goods train-No.1766. 1.What was the cause of the fire？ A．A heavy rain. B．High temperature. C．Carelessness. D．Fear. 2.When did the accident happen？ A．At 00:17 am. B．At 00:17 pm. C．At seventeen past one D．At seventeen to one 3.Where did the accident happen？ A．In Wuchang. B．In Guangzhou. C．In Hubei. D．In Guangdong. 4.The underlined word “extinguish” in the passage most probably means        . A．put out B．put up C．come up D．come out 5.In which direction did the passenger train travel？ A．Northward. B．Southward. C．Eastward. D．Westward.