Maths---送分題

1. (x-1)(x-2)(x-3)(x-4)
=(x^2-3x+2)(x^2-7x+12)
=x^4-7x^3+12x^2-3x^3+21x^2-36x+2x^2-14x+24
=x^4-10x^3+35x^2-50x+24
2 (x^2+1)(x^2+2)
=x^4+3x^2+2
3 (x^2+1)(x+1)(x-1)
=(x^2+1)(x^2-1)
=x^4-1

2007-08-15 17:19:30 補充：
一次因式, 二次因式 is it with a variable like x? And please help me to expand them,I may expand them wrongly.

2007-08-15 17:20:59 補充：
1 has the same factor 1 only , no factors with x^1 or above

一囉

我好肯定的

你唔好易d(講笑)