已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值 已知a=13/19,b=-1/4,求已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值已知a=13/19,b=-1/4,求(a+b)²-2(a²-b²)+(b-a
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![已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值 已知a=13/19,b=-1/4,求已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值已知a=13/19,b=-1/4,求(a+b)²-2(a²-b²)+(b-a](/uploads/image/z/1835051-59-1.jpg?t=%E5%B7%B2%E7%9F%A5x%3Da%2Bb%2Cy%3Da-b%2C%E6%B1%82%EF%BC%88x%26%23178%3B%2By%26%23178%3B%EF%BC%89%26%23178%3B-%EF%BC%88x%26%23178%3B-y%26%23178%3B%EF%BC%89%26%23178%3B%E7%9A%84%E5%80%BC+%E5%B7%B2%E7%9F%A5a%3D13%2F19%2Cb%3D-1%2F4%2C%E6%B1%82%E5%B7%B2%E7%9F%A5x%3Da%2Bb%2Cy%3Da-b%2C%E6%B1%82%EF%BC%88x%26%23178%3B%2By%26%23178%3B%EF%BC%89%26%23178%3B-%EF%BC%88x%26%23178%3B-y%26%23178%3B%EF%BC%89%26%23178%3B%E7%9A%84%E5%80%BC%E5%B7%B2%E7%9F%A5a%3D13%2F19%2Cb%3D-1%2F4%2C%E6%B1%82%EF%BC%88a%2Bb%29%26%23178%3B-2%28a%26%23178%3B-b%26%23178%3B%29%2B%28b-a)
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已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值 已知a=13/19,b=-1/4,求已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值已知a=13/19,b=-1/4,求(a+b)²-2(a²-b²)+(b-a
已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值 已知a=13/19,b=-1/4,求
已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值
已知a=13/19,b=-1/4,求(a+b)²-2(a²-b²)+(b-a)²
求证:81^7-27^9-9^13能被45整除
已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值 已知a=13/19,b=-1/4,求已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值已知a=13/19,b=-1/4,求(a+b)²-2(a²-b²)+(b-a
(x²+y²)²-(x²-y²)²
=(x²+y²+x²-y²)(x²+y²-x²+y²)
=4x²y²
=4(a+b)²(a-b)²
=4(a²-b²)²
=4a^4-8a²b²+4b^4
(a+b)²-2(a²-b²)+(b-a)²
=a²+2ab+b²-2a²+2b²+a²-2ab+b²
=4b²
=4(-1/4)²
=1/4
81^7-27^9-9^13
=9^14-3×9^13-9^13
=9^13(9-3-1)
=5×9^13
=5×9×9^12
=45×9^12
包含因子45,81^7-27^9-9^13能被45整除