题目

代数式x2+x+3的值为7，则代数式﹣3的值为_____． 答案：【答案】-2【解析】根据已知代数式的值为7，求出x2+x的值，原式变形后代入计算即可求出值．解：∵x2+x+3=7，∴x2+x=4，则原式=(x2+x)−3=1−3=-2.故答案为：-2.Hannah ________me; otherwise, other students wouldn't have known my result of the quiz. [     ]A. may betray       B. must betray             C. must have betrayed    D. should betray