题目内容
利用因式分解计算.
(1)1.2222×9-1.3332×4;
(2)
;
(3)1-22+32-42+52-62+…+992-1002.
(1)1.2222×9-1.3332×4;
(2)
| 20083-2×20082-2006 |
| 20083+20082-2009 |
(3)1-22+32-42+52-62+…+992-1002.
(1)原式=(1.222×3+1.333×2)(1.222×3-1.333×2)=6.332×1=6.332;
(2)原式=
=
=
;
(3)原式=(1+2)(1-2)+(3+4)(3-4)+(5+6)(5-6)+…+(99+100)(99-100)
=-1-2-3-4-5-6-…-99-100
=-5050.
(2)原式=
| 20082(2008-2)-2006 |
| 20082(2008+1)-2009 |
| 2006(20082-1) |
| 2009(20082-1) |
| 2006 |
| 2009 |
(3)原式=(1+2)(1-2)+(3+4)(3-4)+(5+6)(5-6)+…+(99+100)(99-100)
=-1-2-3-4-5-6-…-99-100
=-5050.
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