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標題: Quadratic Equations in One Unknown [打印本頁]

作者: LAM941321 時間: 10-10-24 08:12 PM 標題: Quadratic Equations in One Unknown

(A) Factorize m^2+2mn+n^2
               =(m+n)^2
(B) Using the result of (A), factorize a^2+2ab+b^2-c^2
                                                   =(a+b)^2-c^2
                                                   =(a+b)^2-2(a+b)(c)+c^2+2(a+b)(c)
                                                   =(a+b+c)^2
   Are me correct?!?!If not , please explain.
(C) Factorize z^2-4z+4
               =(z-2)^2
(D)  Using the result of (C), factorize x^2+4xy+4y^2-4(x+2y)+4
↑This one i don't know how to do it , please teach me.

[ 本帖最後由 LAM941321 於 10-10-24 08:31 PM 編輯 ]

作者: abcdefg111 時間: 10-10-24 08:53 PM

(A) Factorize m^2+2mn+n^2
               =(m+n)^2
(B) Using the result of (A), factorize a^2+2ab+b^2-c^2
                                                   =(a+b)^2-c^2
                                                   =(a+b+c)(a+b-c)

(C) Factorize z^2-4z+4
               =(z-2)^2
(D)  Using the result of (C), factorize x^2+4xy+4y^2-4(x+2y)+4
= (x+2y)^2 -4(x+2y)+4
=(x+2y-2)^2    from (c)

作者: LAM941321 時間: 10-10-24 10:07 PM

原帖由 abcdefg111 於 10-10-24 08:53 PM 發表
(A) Factorize m^2+2mn+n^2
               =(m+n)^2
(B) Using the result of (A), factorize a^2+2ab+b^2-c^2
                                                   =(a+b)^2-c^2
                  ...

(B) Using the result of (A), factorize a^2+2ab+b^2-c^2
=(a+b)^2-c^2
可吾可以詳細d吾好跳steps

作者: abcdefg111 時間: 10-10-24 10:21 PM

用呢條式: a^2 - b^2 = (a+b)(a-b)
let A=(a+b) c=B
A^2 - B^2
=(A+B)(A-B)
=(a+b+c)(a+b-c)
再乘開佢: (a+b)^2 +(a+b)c -(a+b)c -c^2 =原本果個

[ 本帖最後由 abcdefg111 於 10-10-24 10:22 PM 編輯 ]

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