我想問:(要步驟,答案,原因)
1.)因式分解6( r - 1 ) ( r - 1 ) + 8 ( r - 1 )
=?
2.)因式分解( x + y ) ( x + y ) - 49
=?
2題中二math:因式分解(中文) 快!!!!
2008-11-11 1:57 am
回答 (4)
2008-11-11 6:39 am
✔ 最佳答案
1.)6( r - 1 ) ( r - 1 ) + 8 ( r - 1 )
=2(r-1)[3(r-1)+4]..............................抽公因式
=2(r-1)(3r-3+4)
=2(r-1)(3r+1)
2.)
( x + y ) ( x + y ) - 49
=(x+y)²-49
=(x+y)²-(7)²
=(x+y-7)(x+y+7).....................a²-b²=(a+b)(a-b)
參考: 會考數學拿C既人~
2008-11-12 12:58 am
1.6( r - 1 ) ( r - 1 ) + 8 ( r - 1 )
=(r-1)[6(r-1)+8]
=(r-1)(6r-6+8)
=(r-1)(6r+2)
=2(r-1)(3r+1)
2.( x + y ) ( x + y ) - 49
=(x+y)^2 -7^2
=(x+y+7)(x+y-7)
2008-11-11 16:59:05 補充：
a²-b²=(a+b)(a-b)
=(r-1)[6(r-1)+8]
=(r-1)(6r-6+8)
=(r-1)(6r+2)
=2(r-1)(3r+1)
2.( x + y ) ( x + y ) - 49
=(x+y)^2 -7^2
=(x+y+7)(x+y-7)
2008-11-11 16:59:05 補充：
a²-b²=(a+b)(a-b)
2008-11-11 7:19 am
1) 6(r-1)(r-1)+8(r-1)
=(6r-6)(r-1)+8r-8
=6r^2-6r-6r+6+8r-8
=6r^2-4r-2
=(r-1)(3r+1)
---------------------------------
2) (x+y)(x+y)-49
=(x+y)^2-7^2
=[(x+y)+7][(x+y)-7]
=(x+y+7)(x+y-7)
------------------------------------
=(6r-6)(r-1)+8r-8
=6r^2-6r-6r+6+8r-8
=6r^2-4r-2
=(r-1)(3r+1)
---------------------------------
2) (x+y)(x+y)-49
=(x+y)^2-7^2
=[(x+y)+7][(x+y)-7]
=(x+y+7)(x+y-7)
------------------------------------
參考: myself
2008-11-11 2:03 am
1.6( r - 1 ) ( r - 1 ) + 8 ( r - 1 )
=(r-1)[6(r-1)+8]
=(r-1)(6r-6+8)
=(r-1)(6r+2)
2.( x + y ) ( x + y ) - 49
=(x+y)^2 -7^2
=(x+y+7)(x+y-7)
=(r-1)[6(r-1)+8]
=(r-1)(6r-6+8)
=(r-1)(6r+2)
2.( x + y ) ( x + y ) - 49
=(x+y)^2 -7^2
=(x+y+7)(x+y-7)
參考: me
收錄日期: 2021-04-23 18:09:37
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081110000051KK01128