利用因式分解计算（要过程

3.14X56的平方-3.14X44的平方
= 3.14 * (56^2 - 44^2)
= 3.14 * (56 + 44) * (56 - 44)
= 3.14 * 100 * 12
= 314 * 12
= 3768
800的平方-1600X798+798的平方
= 800^2 - 1600 * 798 + 798^2
= 800^2 - 798 * (1600 - 798)
= 800^2 - 798 * 802
= 800^2 - (800 - 2) * (800 + 2)
= 800^2 - (800^2 - 2^2)
= 800^2 - 800^2 + 2^2
= 4
2007的平方/2006X2008+1
= 2007^2 / (2006 * 2008 + 1)
= 2007^2 / [(2007 - 1) * (2007 + 1) + 1]
= 2007^2 / [2007^2 - 1^2 + 1]
= 2007^2 / 2007^2
= 1