20分數學問題!Factorize the following polynomials

6x*+5x+1 = (2x+1)(3x+1)

2y*+5y+2 = (2y+1)(y+2)

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As you know (Ax+C)(Bx+D) = (AB)x* + (AD+BC)x + CD
So,
1st) think about the possible sets of A&B
2nd) think about the possible sets of C&D
Final) try & error to find the right A,B,C,D for AD+BC
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6x +5x+ 1
=6x(2) +5x +1
=36x +5x+ 1
=41x +1


2y* +5yx +2
=2y(2)+5y+ x2
=4y +5y +2
=9y +2

6x*+5x+1

=6xx+5x+1

=(3x)(2x)+3x+2x+1

=(3x+1)(2x)+3x+1

=(3x+1)(2x+1)+1-1

=(3x+1)(2x+1)




2y*+5y+2

=2yy+2y+2y+1y+2

=(2y)(1y)+2y+2y+1y+2

=(2y)(1y+2)+1y+2

=(2y+1)(1y+2)+2-2

=(2y+1)(1y+2)

係叫你恩式分解吧= ="(吳色english啊/口\
恩式分解有兩個方法 交叉相乘 同 計算機= =|
6x*+5x+1
=(3x+1)(2x+1)

2y*+5y+2
=(2x+1)(x+2)

注 : 廿一世紀,學校應該有教你用計算機架喎= =

2008-10-26 17:01:01 補充：
2y*+5y+2
=(2y+1)(y+2)



001 全錯啦= = 佢無睇倒係2次.....

002 都錯= ="
(x+1)(6x+1) 展開係 6x*+7x+1............

(y+2)(2y+2) 展開係2y*+6y+4............

6xx + 5x +1
= 6xx + 6x - x+1
= 6x(x+1) - ( x+1)
= (x+1)(6x+1)

2yy + 5y +2
=2yy + 4y + y + 2
= 2y( y+2 ) + (y+2)
= (y+2)(2y+2)

6x +5x+ 1
=6x(2) +5x +1
=36x +5x+ 1
=41x +1


2y* +5yx +2
=2y(2)+5y+ x2
=4y +5y +2
=9y +2