问题
解答题
计算: (1)(2a-b)(b+2a)-(3a+b)2 (2)(
(3)简便方法计算:(-0.25)2009×42010. |
答案
(1)原式=4a2-b2-(9a2+6ab+b2)
=4a2-b2-9a2-6ab-b2
=-5a2-2b2-6ab;
(2)原式=4-1=3;
(3)原式=(-0.25)2009×42009×4=(-0.25×4)2009×4=-1×4=-4.
故答案为-5a2-2b2-6ab、3、-4.