题目内容
计算:
(1)(-2m+n)2:
(2)(-2m-n)2:
(3)(2a+b)2-(2a-b)2.
(1)(-2m+n)2:
(2)(-2m-n)2:
(3)(2a+b)2-(2a-b)2.
(1)(-2m+n)2
=(-2m)2-2•2m•n+n2
=4m2-4mn+n2;
(2)(-2m-n)2
=(-2m)2+2•(-2m)•(-n)+(-n)2
=4m2+4mn+n2;
(3)(2a+b)2-(2a-b)2
=(4a2+4ab+b2)-(4a2-4ab+b2)
=8ab.
=(-2m)2-2•2m•n+n2
=4m2-4mn+n2;
(2)(-2m-n)2
=(-2m)2+2•(-2m)•(-n)+(-n)2
=4m2+4mn+n2;
(3)(2a+b)2-(2a-b)2
=(4a2+4ab+b2)-(4a2-4ab+b2)
=8ab.
练习册系列答案
相关题目
计算:
-
÷
的结果为( )
| m |
| m+3 |
| 6 |
| 9-m2 |
| 2 |
| m-3 |
| A、1 | ||
B、
| ||
C、
| ||
D、
|