中二數題=====(x-1)^2-144

(x-1)²-144
=x²-2x+1-144
=x²-2x-143

2007-01-25 00:56:15 補充：
方法1-------用十字相乘法計算 (x-1)²-144=x²-2x 1-144=x²-2x-143當你做到x²-2x-143你可以用十字相乘法:=(x-13)(x 11)－－－－－－－－－－－－－－－－－－－－－－－－－方法2------用平方差計算 (x-1)²-144=(x-1)²-12²=(x-1-12)(x-1 12)=(x-13)(x 11)2種方法都計到

(x-1)^2-144
=(x-1)^2-12^2
=[(x-1)-12][(x-1)+12]
=(x-13)(x-11)

(x-1)^2-144
=(x-1)^2-12^2
=[(x-1)-12][(x-1)+12]
=(x-13)(x-11)

2007-01-28 00:38:09 補充：
十字相乘法 is ok but it is not covered in form 2. Moreover, it is not a good method for this question since we saw a^2-b^2 patten in this question.