Question

因式分解~20分~急

Answer 1

1. x^2-25 解：x^2-25 =x^2-5^2 =(x+5)(x-5) 2. 4x^2-1 解：4x^2-1 =(2x)^2-1^2 =(2x+1)(2x-1) 3. 9x^2-25 解：9x^2-25 =(3x)^2-5^2 =(3x+5)(3x-5) 4. 49x^2-100 解：49x^2-100 =(7x)^2-10^2 =(7x+10)(7x-10) 5. 4x^2-9y^2 解：4x^2-9y^2 =(2x)^2-(3y)^2 =(2x+3y)(2x-3y) 6. 2x^2-50 解：2x^2-50 =2(x^2-25) =2(x+5)(x-5) 7a.x^2+4x+4 解：x^2+4x+4 =x^2 + 2*2*x^2 + 2^2 =(x+2)^2 b.x^2+4x+4y-y^2 解：x^2+4x+4y-y^2 =(x^2-y^2)+(4x+4y) =(x+y)(x-y)+4(x+y) =(x+y)(x-y+4) 8a. x^2+4xy+4y^2 解：x^2+4xy+4y^2 =(x+2y)^2 b. x^2+4xy+4y^2-z^2 解：x^2+4xy+4y^2-z^2 =(x^2+4xy+4y^2)-z^2 =(x+2y)^2-z^2 =(x+2y+z)(x+2y-z) 2010-08-30 13:25:09 补充： 9a. r^2-10rs+25s^2 解：r^2-10rs+25s^2 =r^2-2*r*5s+(5s)^2 =(r-5s)^2 b. r^2-10rs+25s^2-t^2 解：r^2-10rs+25s^2-t^2 =(r-5s)^2-t^2 =(r-5s+t)(r-5s-t)
参考: Hope I can help you
1. ( x + 5 ) ( x - 5 ) 2. ( 2x + 1 ) ( 2x - 1 ) 3. ( 3x + 5 ) ( 3x - 5 ) 4. ( 7x + 10 ) ( 7x - 10 ) 5. ( 2x - 3y ) ( 2x + 3y ) 6. 2 ( x + 5 ) ( x - 5 ) 2010-08-30 13:19:27 补充： 7a.x^2+4x+4 = ( x + 2 ) ^ 2 2010-08-30 13:22:05 补充： 8a. x^2+4xy+4y^2 = ( x + 2y ) ^2 2010-08-30 13:22:29 补充： 9a. r^2-10rs+25s^2 = ( r + 5s ) ^ 2