复习题2第1题答案
(1)(t+15)°C
(2)nc元,(100- nc)元
(3)0.8b元,(0. 8b-10)元
(4)a/30m,1 500 m,(a/30-1 500)m
复习题2第2题答案
复习题2第3题答案
(1)-2x2y
(2)10. 5y2
(3)0
(4)-1/12mn+7
(5)8ab2+4
(6)3x3-2x2
复习题2第4题答案
(1)原式=4a3 b-10b3-3a2 b2 +10b3=4a3 b- 3a22b2
(2)原式=4x2 y-5xy2-3x2y+4xy2=x2y-xy2
(3)原式=5a2-(a2+5a2-2a-2a2+6a)=5a2-a2-5a2+2a+2a2-6a=a2-4a
(4)原式=15+3-3a-1+a+a2+1-a+a2-a3=18-3a+2a2-a3
(5)原式=4a2b-3ab-5a2b+2ab=a2b-ab
(6)原式=6m2-4m-3+2m2-4m+1=8m2-8m-2
(7)原式=5a2+2a-1-12+32a-8a2=-3a2+34a-13
(8)原式=3x2-(5x-1/2x+3+2x2)=3x2-5x+1/2x-3-2x2=x2-9/2x-3
复习题2第5题答案
解:原式=(5-3-2)x2+(-5+6)x-1=x-1
当x=-3时
原式=-3-1=-4
复习题2第6题答案
(1)5/2
(2)(x+y)/10