题目

求圆心在直线x+y=0上，且过两圆x2+y2-2x+10y-24=0，x2+y2+2x+2y-8=0的交点的圆的方程. 答案：圆的方程为(x+3)2+(y-3)2=10. 解析:解方程组得交点坐标分别为(0,2),(-4,0). 设所求圆的圆心坐标为(a,-a), 则. 解得a=-3,. 因此,圆的方程为(x+3)2+(y-3)2=10.完形填空（10小题，每小题1分，共10分）Francis is walking on the street of a foreign city. He can 16 a person about 200 meters from him. The person seems to be a girl. She is holding a large piece of 17 high above her head. He cannot see what is on the paper, so he keeps on 18 towards the girl.As he comes closer, he can see the girl 19 . She is about 20 years old. She is tall and slim with black hair. And he can also see the words on the paper: FREE HUGS. Francis does not understand. He goes to the girl but 20 ten meters from her. The girl looks at him, smiling. A woman goes to the girl. The girl hugs 21 . Then the woman goes away 22 a big smile. Now Francis understands. 23 can go to the girl and hug her for free. Francis is surprised. He thinks this is a 24 idea. He goes to the girl to hug her. When they are finished, he thanks the girl. The girl smiles at him and she 25 him, too. Then he walks away from the girl. He feels stronger, younger and happier.【1】 A. smell B. see C. feel D. sound【2】A. cake B. cloth C. paper D. wood【3】A. looking B. jumping C. leaving D. walking【4】A. clearly B. carefully C. hardly D. lately【5】A. helps B. runs C. lies D. stops【6】A. them B. it span> C. her D. him【7】A. without B. with C. from D. except【8】A. Everyone B. None C. Everything D. Nothing【9】A. bad B. wonderful C. strange D. rude【10】A. likes B. leaves C. greets D. thanks