文档介绍：: .
平方差公式
1. 计算
(I) (-2x2 5)(—2x2 -5)
(3) (-4a-1)(4a-1) (4
(5) (3a -2b)(3a 2b)(9a2 4b2)
(7) (a+2)( a2+4)( a4+16) (a - 2)
(9) 19982-1997 X 1999
(II) 2009X 2007 -20082
2. 计算
⑴(3 n)(-3 n) -(3n-1)(-3n-
(m2 1)(m 1)(m-1) -(m4 1)
(2) (ab 4)(ab - 4)
)(-1+3x) (-1-3x )
2 4
(6) (1-a)(1 a)(1 a )(1 a )
(8) (x4 1)(x2 1)(x 1)(x-1)
(10) 2003X 2001 - 20022
(12) 20112 - 2010 2012
1) ⑵
⑶(2x - 3y)(3y 2x) -(4y - 3x)(3x 4y) ⑷ a4+(1 -
a)(1+a)(1+a 2)
⑸- 3 x 1 x - 1 - 3x 2 2 - 3x ⑹
(a 3)(a - 3) -(a -1)(a 4)
3. 先化简，再求值：
(1) (3m - 4n )(4 n 3m) -(2 m 3n )(2m _n)，其中 m=1,n = _1.
⑵(3x+2)(3x-2) -(x+1)