3．设x?13?2,y?13?2，求代数式x?xy?yx?y22的值．
4．当3a?ab?2b?0(a?0,b?0)，求
22ab?ba?a?bab22的值．
5．设x、y为实数，且xy?3，求x120120yx?y120xy的值．
2226．已知a?的值． 7．设x?x?20,b?x?19,c?x?21，求代数式a?b?c?ab?bc?ac5?12，求x4?x2?2x?1的值．
8．展开(x?2)4
9．计算(x?1)(x?2)(x?3)(x?4)
10．计算(x?y?z)(?x?y?z)(x?y?z)(x?y?z) 11．化简或计算：
(1) (18?412?12?32)?331
(2) 223?2?(2?5)?5?2
(3)
xx?xxy?y2y?x?xxy?yx?ya
ybab?aa?bab
(4) (a?b?a?abb)?(ab?b??)
第一讲 习题答案 A组
1． C 2． A
3． (1) x2?9y2?16z2?6xy?8xz?24yz
(3) ?3a2b?3ab2
b)
2(2) 3a2?5ab?3b2?4a?2b?1 (4)
14a?16b
33
4．?2a?2a ??a 2(a? ??1
a?b25．mm 2xy B组
1． D 2．a?c?b?2ac,32?23 4．?3,2
5．?23
6． 3
8．x4?8x3?24x2?32x?16 9．x4?10x3?35x2?50x?24
10．?x4?y4?z4?2x2y2?2x2z2?2y2z2
11．?3,43,x?y3y,b?a
3． ?1363
7．3?5