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阅读理解 Learn English in New ZealandLearn English in New Zealand at Language Schools New Zealand(LSNZ). Our Christchurch and Queenstown schools in the South Island of NZ arethe perfect places to learn English.What is your dream?Do you dream of speaking English very well?Do you dream of travel, making friends, a lifestyle usingEnglish?LSNZ will help youto achieve your dream!Language Schools New Zealand Christchurch and Queenstownare in the fascinating South Island of New Zealand. Both English schools are fullyrecognized (认证) by NZQA and are in beautiful NZ places. LSNZ offers manyki在平面直角坐标系xOy中，记二次函数f（x）=x2+2x+b（x∈R）与两坐标轴有三个交点．经过三个交点的圆记为C．（1）求实数b的取值范围；（2）求圆C的方程；（3）问圆C是否经过定点（其坐标与b的无关）？请证明你的结论．