课前预习答案
1、每一项;每一项;相加
2、ma+mb+na+nb
课堂探究例1思路导引答案
符号
解:(1原式=3a.4a+3a.(-5b)+2b•4a+2b.(-5b)
=12a2 -15ab+8ab-10b2
=12a2-7ab-10b2;
(2)原式=x.x4+x.x2+x.(-2)+(-1). x4+(-1).x2+(-1) •(-2)
=x5+x3 -2x-x4-x2+2
=x5-x4+x3-x2-2x+2
课堂探究例1变式训练1-1答案
B
课堂探究例1变式训练1-2答案
解:原式=x.x2 +x.(-xy) +x.y2 +y.x2 +y.(-x-y) +y.y2
=x3-x2y+xy2+x2y-xy2+y3
=x3+y3
课堂探究例2思路导引答案
(10x2-2x+15x-3)
解:原式=5x.2x+5x.1-[2x.5x+2x.(-1)+3•5x+3.(-1)]
=10x2+5x-(10x2-2x+15x-3)
=10x2+5x-10x2+2x-15x+3
= -8x+3
当x=13时,原式=-8×13+3= -101
课堂探究例2变式训练2-1答案
B
课堂探究例2变式训练2-2答案
-2