根据短文内容，完成下列任务。

    It's a sunny Sunday. Mrs. Green is on a bus. She sees a woman get on the bus with ten boys. All the boys wear (穿) the same clothes —blue coats and black trousers.

    “Are these all your sons?” Mrs. Green asks the woman.

    “Yes, they are,” says the woman.

    “Where are you going?” asks Mrs. Green.

    “My sons want to play in the park.”

    “Why do they wear the same clothes?” asks Mrs. Green.

    “Because it's easy to see them. When I have three sons, I dress( 给……穿衣服) them in the same clothes because I don't want to lose any of them. But now I have ten sons, and I let them wear the same clothes. I don't want to take other boys home,” says the woman.

若（x﹣5）（x+20）=x²+mx+n，则m、n的值分别为（　　）

设随机变量X～$B(6,\frac{1}{2})$，则P(X=3)的值是(    )