题目

已知x2﹣y2=14，x﹣y=7，则________ 答案：【答案】2．【解析】试题根据平方差公式可知，x2﹣y2=（x+y）（x﹣y）=14，又x﹣y=7，则x+y=2，故答案为：2． He was sad for ________ any chance of his going to college.A．there being notB．there not beingC．not there beingD．not being