2. Factorize the following expressions.
a)12y+20-9y^3-15y^2 b) (x^2-6x+9)-4y^2
3.If5(x+2)^2-2x93+x)=Ax^2+Bx+C,Find A,B and C.
MAth >.
2009-05-23 6:34 am
回答 (1)
2009-05-23 7:42 pm
✔ 最佳答案
2a. = 4(3y + 5) - 3y^2 ( 3y + 5)= (3y + 5)( 4 - 3y^2)
2b. = ( x - 3)^2 - (2y)^2
= [(x -3) + 2y][(x - 3) - 2y]
= ( x + 2y -3)(x - 2y -3)
3.
5(x^2 + 4x + 4) - 6x - 2x^2
= 5x^2 + 20x + 20 - 6x - 2x^2
= 3x^2 + 14x + 20 which is identical to Ax^2 + Bx + C.
so A = 3, B = 14 and C = 20.
2009-05-23 13:26:57 補充：
2a can be factorized further to (3y + 5)(2 - sqrt3 y)(2 + sqrt 3 y) if necessary.
收錄日期: 2021-04-25 22:36:52
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090522000051KK01654