题干

如图,在边长为a的正方形中挖掉一个边长为b的小正方形(a>b),把余下的部分剪拼成一矩形如图,通过计算两个图形(阴影部分)的面积,验证了一个乘法公式,则这个乘法公式是____.

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(a+b)(a﹣b)=a2﹣b2

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    British Museum Visitor Regulations

    We warmly welcome you on your visit to the Museum. In the interests of the security of all of our visitors we require you follow these Visitor Regulations.

    Admission

    Admission to the Museum is free, but we may charge for entry to some temporary exhibitions and events.

    Opening hours

    We open the Museum's galleries daily from 10:00 am until 17:30 pm. We keep selected galleries open until 20:30 pm on Fridays.

    The Museum's Great Court is open from 9:00 am until 18:00 pm; except on Fridays when it remains open until 20:30 pm.

    You may be asked by your staff to begin leaving up to ten minutes before closing time.

    The Museum is closed 24 -26 December and l January.

    Food and drink

    You aren't allowed to consume food and drink inside the Museum, except in places such as the restaurant and cafes or the forecourt. Families with children may use the Ford Centre for young visitors in the basement of the Museum's Great Court at weekends and during school holidays.

    Animals

    If you have a disability, you may be accompanied in the Museum by your guide, assistant or companion animal. You aren't allowed to bring animals into the Museum under any other circumstance.

    Film, photography and audio(声音的)recording

    Except the place that are indicated by notices, you' re permitted to use hand- held cameras (including mobile phones) with flash bulbs or flash units, and audio and film recording equipment not requiring a stand. You may use your photographs, film and audio recordings only for your own private and non-commercial purposes.