习题3.3第1题答案
(1)2a+2b
=2×2+2×3
=4+6
=10
(2)2(a+b)
=2×(2+3)
=2×5
=10
(3)a2b2
=22×32
=4×9
=36
(4)(ab)2
=(2×3)2
=62
=36
(5)a2+b2
=22+32
=4+9
=13
(6)(a+b)2
=(2+3)2
=52
=25
(7)a2+2ab+b2
=22+2×2×3+32
=4+12+9
=25
(8)2(2a-b)3-(2a-b)2+8(2a-b)
=2×(2×2-3)3-(2×2-3)2+8×(2×2-3)
=2×1-1+8×1
=2-1+8
=9
习题3.3第2题答案
解:表格从左至右依次填-15,-13,-11,-7,-5,-4,-2.2
习题3.3第3题答案
解:图中从上至下依次填×2,-3,×5;
表格从左至右依次填-25,-20,-15,0,5,10,43.9
习题3.3第4题答案
解:因为当tF=64.4°F时,
tC=5/9×(64.4-32)=5/9×32.4=18(℃),
所以这两地的气温相同。
习题3.3第5题答案
解:(1)①a2-πa2/4
②a2-πa2/4
③a2-πa2/4
(2)①100-25π
②100-25π
③100-25π
习题3.3第6题答案
解:图①的面积为a2-b2
图②的面积为(a+b)×(a-b)
习题3.3第7题答案
提示:S球表面=4πr2
V球=4/3 πr3
S地球≈5.1×108 (km2 )
V地球≈1.1×1012 (km3 )