计算:(1)(a-2b+3c)2;(2)(3x+y-2)(3x-y+2).
题型:解答题难度:一般来源:不详
计算: (1)(a-2b+3c)2; (2)(3x+y-2)(3x-y+2). |
答案
(1)(a-2b+3c)2 =(a-2b)2+9c2-6c(a-2b) =a2-4ab+4b2+6ac-12bc+9c2;
(2)(3x)2-(y-2)2=9x2-y2+4y-4. |
举一反三
计算: (1)(2x+y-3z)2; (2)(x-y+4)(x+y+4). |
计算(x-3y)(x+3y)的结果是( )A.x2-3y2 | B.x2-6y2 | C.x2-9y2 | D.2x2-6y2 |
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499×501可表示为( )A.5002+12 | B.5002-12 | C.5002-4992 | D.5002+4992 |
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