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【350053】湘教版七年级数学下册课后作业:2.1.3单项式的乘法(含答案)

时间:2025-03-06 06:41:15 作者: 字数:2919字
简介:

课时作业(十)

单项式的乘法

 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> (30分钟 50)

一、选择题(每小题4,12)

1.(2013·绍兴中考)计算3a·2b的结果是(  ) <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a>

A.3ab B.6a C.6ab D.5ab

2.下列计算中,错误的是(  )

A.(2xy)3(-2xy)2=32x5y5[来源:Zxxk.Com]

B.(-2ab2)2(-3a2b)3=-108a8b7

C. <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> =x4y3

D. <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> = <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> m4n4

3.某商场4月份售出某品牌衬衣b,每件c,营业额a.5月份采取促销活动,售出该品牌衬衣 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 3b,每件打八折,5月份该品牌衬衣的营业额比4月份增加(  )

A.1.4a B.2.4a

C.3.4a D.4.4a

二、填空题(每小题4,12)

4.(2013·泰州中考)计算:3a·2a2=    .

5.计算: <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> =    .

6.光的速度约为 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 3×105km/s,太阳光到达地球需要的时间约为5×102s,则地球与太阳间的距离约为   km.

三、解答题(26)

7.(8)计算:(1)4y3·(-2x2y).

(2) <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> x2y3· <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> xyz <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> .

(3)(3x2y)3·(-4xy2).

(4)(-xy2z3)4·(-x2y)3.

8.(8)有理数x,y满足条件|2x-3y+ <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 1|+(x+3y+5)2=0,求代数式

(-2xy)2·(-y2)·6xy2的值.

【拓展延伸】

 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 9.(10)已知三角 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 表示2abc,方框 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 表示(-3xzω)y, <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> × <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> .

 

 

答案解析

1.【解析】C.3a·2b=3×2a·b=6 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> ab.

2.【解析】D.选项A,(2xy)3(-2xy)2=8x3y3×4x2y2=32x5y5,故此选项正确;选项B,(-2ab2)2(-3a2b)3= <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 4a2b4×(-27)a6b3=-108a8b7,故此选项正确;选项C, <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> = <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> x2y2× <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> x2y=x4y3,故此选项正确;选项D, <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> = <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> m2 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> m <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 2n4= <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> m4n5,故此选项错误.

3.【解析】A.由题意知bc=a.因为5月份售出该品牌衬衣3b,每件打八折,则每件为0.8c.所以5月份该品牌衬衣的营业额为:3b·0.8c=2 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> .4bc=2.4a().所以5月份该品牌衬衣的营业额比4月份增加2.4a-a=1.4a().

4.【解析】3a·2a2=6a3.

答案:6a3

5.【解析】 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a>

= <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> (a·a2)(b2·b)

=-a3b3.

答案:-a3b3

6.【解析】(3×105)×(5×102)=(3×5)×(105×102)

=15×107=1.5×108.

答案:1.5×108

7.【解析】(1)原式=[4×(-2)]x2·(y3·y)=-8x2y4.

(2)原式= <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> (x2·x)(y3·y)·z

= <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> x3y <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 4z.

(3)原式=27x6y3·(-4xy2)

=[27×(-4)](x6·x)(y3·y2)

=-108x7y5.

(4)原式=x4y8z12·(-x6y3)

=-(x4·x6)(y8·y3)z12

=-x10y11z12.

 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 8.【解题指南】|2x-3y+1|+(x+3y+5)2=0,2x-3y+1=0,x+3y+5=0,建立 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 方程组,解得x,y,代入代数式求值.

【解析】由题意得 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 可得 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a>

所以(-2xy)2·(-y2)·6xy2

=4x2y2·(-y2)·6xy2=-24x3y6.

x=-2,y=-1,

原式=-24×(-2)3×(-1) <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> 6=-24×(-8)=192.

9.【解析】 <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> × <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/195/" title="乘法" class="c1" target="_blank">乘法</a> <a href="/tags/381/" title="作业" class="c1" target="_blank">作业</a> <a href="/tags/877/" title="单项式" class="c1" target="_blank">单项式</a> =2mn3·(-3n5m)2=2mn3·9n10m2=18n13m3.

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