標題:
2題中二math:因式分解(中文) 快!!!!
發問:
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 =?
最佳解答:
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)
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其他解答:
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)|||||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) ------------------------------------|||||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)
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