问题
填空题
设（x2+y2）（x2+y2+2）-15=0，则x2+y2的值为______．
答案
设t=x2+y2，则原式可化为t2+2t-15=0，
∴t=x2+y2=3或t=x2+y2=-5，
又∵t≥0，
∴x2+y2=3．
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设（x2+y2）（x2+y2+2）-15=0，则x2+y2的值为______．
设t=x2+y2，则原式可化为t2+2t-15=0，
∴t=x2+y2=3或t=x2+y2=-5，
又∵t≥0，
∴x2+y2=3．
My two-year-old daughter Kate wanted a dog. But I was too busy to buy one. One day, Kate ran in, shouting, “Mom! Come to see my dog!” Her face was red with __36__. I followed her to the bush and found a __37__! He was hurt. Seeing me, he stood up __38__! I could see his teeth! God! My mouth felt __39__. “Don’t be afraid. That’s mom. She loves you, too.” Kate said. Then he became friendly. It was __40__! I __41__to find my husband and told him about the wolf. We should have killed the wolf, __42__Kate loved him. Besides, he was gentle to Kate. So we called the vet(兽医）finally. Kate named the wolf Ralph __43__ she carried food to him every day. Later, Ralph got well. They played together in the daytime. At night, Ralph would return to the mountains. Sometimes he __44__but came back several days later. On Kate’s first day of school, we could see Ralph’s __45__. After the school bus left, Ralph lay by the side of the road and __46__. When Kate returned, he got happy again. This __47__throughout Kate’s school years. Twelve __48__passed. One day we heard that a she-wolf was killed. The other wolf was hurt and ran away. We were__49__about Ralph. That night, Ralph returned with a wound(伤口). Sixteen-year-old Kate held his head and __50__him. We hope he could come through. However, he __51__. Kate cried. I noticed something strange in the bush-----two little yellow eyes! Ralph’s __52__! Before he died, Ralph __53__his child to us ! He knew he would be __54__here, as he had been. Ralph, Ralph... I was __50__. “Don’t be afraid, little...Ralphie. That’s mom. She loves you, too.”
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