两个数的十位数同为n,个位数分别为a,b,且a,b和为10,结果有什么规律,①在括号中填上合适的项:a+b-c=a+( ),a-b+c=a-( );②根据①中信息,计算下列各式的值:(a+b-c)²=(a-b+c)²=(2x-y-3)²=(2x+y-1)
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![两个数的十位数同为n,个位数分别为a,b,且a,b和为10,结果有什么规律,①在括号中填上合适的项:a+b-c=a+( ),a-b+c=a-( );②根据①中信息,计算下列各式的值:(a+b-c)²=(a-b+c)²=(2x-y-3)²=(2x+y-1)](/uploads/image/z/8734548-12-8.jpg?t=%E4%B8%A4%E4%B8%AA%E6%95%B0%E7%9A%84%E5%8D%81%E4%BD%8D%E6%95%B0%E5%90%8C%E4%B8%BAn%2C%E4%B8%AA%E4%BD%8D%E6%95%B0%E5%88%86%E5%88%AB%E4%B8%BAa%2Cb%2C%E4%B8%94a%2Cb%E5%92%8C%E4%B8%BA10%2C%E7%BB%93%E6%9E%9C%E6%9C%89%E4%BB%80%E4%B9%88%E8%A7%84%E5%BE%8B%2C%E2%91%A0%E5%9C%A8%E6%8B%AC%E5%8F%B7%E4%B8%AD%E5%A1%AB%E4%B8%8A%E5%90%88%E9%80%82%E7%9A%84%E9%A1%B9%EF%BC%9Aa%2Bb-c%3Da%2B%28+%29%2Ca-b%2Bc%3Da-%28+%29%3B%E2%91%A1%E6%A0%B9%E6%8D%AE%E2%91%A0%E4%B8%AD%E4%BF%A1%E6%81%AF%2C%E8%AE%A1%E7%AE%97%E4%B8%8B%E5%88%97%E5%90%84%E5%BC%8F%E7%9A%84%E5%80%BC%EF%BC%9A%28a%2Bb-c%29%26%23178%3B%3D%28a-b%2Bc%29%26%23178%3B%3D%282x-y-3%29%26%23178%3B%3D%282x%2By-1%29%26%23)
两个数的十位数同为n,个位数分别为a,b,且a,b和为10,结果有什么规律,①在括号中填上合适的项:a+b-c=a+( ),a-b+c=a-( );②根据①中信息,计算下列各式的值:(a+b-c)²=(a-b+c)²=(2x-y-3)²=(2x+y-1)
两个数的十位数同为n,个位数分别为a,b,且a,b和为10,结果有什么规律,
①在括号中填上合适的项:a+b-c=a+( ),a-b+c=a-( );
②根据①中信息,计算下列各式的值:
(a+b-c)²=
(a-b+c)²=
(2x-y-3)²=
(2x+y-1)²=
两个数的十位数同为n,个位数分别为a,b,且a,b和为10,结果有什么规律,①在括号中填上合适的项:a+b-c=a+( ),a-b+c=a-( );②根据①中信息,计算下列各式的值:(a+b-c)²=(a-b+c)²=(2x-y-3)²=(2x+y-1)
1) a+b-c=a+(b-c)
a-b+c=a-(b-c)
2) (a+b-c)²=(a+(b-c))²=a²+2a(b-c)+(b-c)²=a²+2ab-2ac+b²-2bc+c²=a²+b²+c²+2ab-2ac-2bc
(a-b+c)²=(a-(b-c))²=a²-2a(b-c)+(b-c)²=a²-2ab+2ac+b²-2bc+c²=a²+b²+c²-2ab+2ac-2bc
(2x-y-3)²=(2x-(y+3))²=4x²-4x(y+3)+(y+3)²=4x²-4xy-12x+y²+6y+9=4x²+y²-4xy-12x+6y+9
(2x+y-1)²=(2x+(y-1))²=4x²+4x(y-1)+(y-1)²=4x²+4xy-4x+y²-2y+1=4x²+y²+4xy-4x-2y+1