2) abx^2+aby^2+a^2xy+b^2xy
3) 9c^2-4l^2+16lm-16m^2
4) (x^2+x)^2-18(x^2+x)+72
5) a^2-4a(x-y)-5(x-y)^2
PS:' ^ ' 姐係 次方~
thx~~
更新1:
sor~ 係抽番d common factor 出黎呀~~ e.g. ab+ac=a(b+c)個d~~ thx~
f.2數學~
2007-02-24 9:07 am
1) x^3 -abx-x^2y+ax^2-bx^2+bxy
2) abx^2+aby^2+a^2xy+b^2xy
3) 9c^2-4l^2+16lm-16m^2
4) (x^2+x)^2-18(x^2+x)+72
5) a^2-4a(x-y)-5(x-y)^2
PS:' ^ ' 姐係 次方~
thx~~
2) abx^2+aby^2+a^2xy+b^2xy
3) 9c^2-4l^2+16lm-16m^2
4) (x^2+x)^2-18(x^2+x)+72
5) a^2-4a(x-y)-5(x-y)^2
PS:' ^ ' 姐係 次方~
thx~~
回答 (2)
2007-02-24 11:24 am
✔ 最佳答案
1) x3 - abx - x2y + ax2 - bx2 + bxy= x (x2 - ab - xy + ax - bx + by)
= x (x2 - xy + ax - bx + by - ab )
= x (x - b) (x - y + a)
2) abx2 + aby2 + a2xy + b2xy
= a2xy + abx2 + aby2 + b2xy
= ax (ay + bx) + by (ay + bx)
= (ax + by) (ay + bx)
3) 9c2 - 4l2 + 16lm - 16m2
= 9c2 - 4(l2 - 4lm + 4m2)
= 9c2 - 4(l - 2m)2
= [3c + 2(l - 2m)] [3c - 2(l - 2m)]
或[3c + 2(l - 2m)] [3c + 2(2m - l)]
4) (x2 + x)2 - 18(x2 + x) + 72
= [(x2 + x) - 6] [(x2 + x) - 12]
= (x2 + x - 6) (x2 + x - 12)
= (x + 3) (x - 2) (x + 4) (x - 3)
5) a2-4a(x - y)-5(x - y)2
= [a + (x - y)] [a - 5(x - y)]
= (a + x - y) [a + 5(y - x)]
2007-02-24 9:11 am
e d maths..... 你係5係play me呀? what's that?? I am also a F.2 student.... but i CAN'T UNDERSTAND THEM..........
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