北师大七年级下1.2幂的乘方与积的乘方专题练习题含答案(最新整理)

北师大版数学七年级下册第1 章整式的乘除

1．2 幂的乘方与积的乘方幂的乘方专题练习题1.计算(a2)3 的结果是( )

A．a5 B．a6 C．a8 D．3a2

2.下列式子的化简结果不是a8 的是( )

A．a6·a2 B．(a4)2 C．(a2)4 D．(a4)4

3．下列各式计算正确的是( )

A．(x3)3＝x6 B．a6·a4＝a24

C．[(－x)3]3＝(－x)9 D．－(a2)5＝a10

4．下列运算正确的是( )

A．a2＋a2＝a4 B．a5－a3＝a2 C．a2·a2＝2a2 D．(a5)2＝a10

5．填空：( )2＝( )3＝( )4＝a12.

6．已知x n＝2，则x3n＝．

7．已知10a＝5，那么100a 的值是( )

A．25 B．50 C．250 D．500

8．若3x＋4y－5＝0，则8x·16y 的值是( )

A．64 B．8 C．16 D．32

9．下列各式与x3n＋2 相等的是( )

A．(x3)n＋2 B．(x n＋2)3 C．x2·(x3)n D．x3·x n＋x2

10．计算(－p)8·[(－p)2]3·[(－p)3]2 的结果是( )

A．－p20 B．p20 C．－p18 D．p18

11．若26＝a2＝4b，则a b 等于( )

A．43 B．82 C．83 D．48

12．若2a＝3，2b＝4，则23a＋2b 等于( )

A．7 B．12 C．432 D．108

13．若3×9m×27m＝321，则m 的值是( )

A．3 B．4 C．5 D．6

14．若a4n＝3，那么(a3n)4＝．

15．若5m＝2，5n＝3，则53m＋2n＋1＝．

16．填空：(1)(－a3)2·(－

a)3＝；

(2)[(x－y)3]5·[(y－x)7]2＝；

(3)a3·(a3)2－2·(a3)3＝

．1

7．计算：

(1)(－x)3·(x3)2·(－x)4；(2)x n－

1·(x n＋2)2·x2·(x2n－1)3；

(3)2(x3)2·x2－3(x2)4＋5x2·x6；

(4)[(a－b)3]2－2(a－b)3·(b－a)3.

18．若x2n＝5，且n 为整数，求(x3n)2－5(x2)2n 的值．

19．已知10m＝2，10n＝3，求103m＋2n 的值．

20．(1)已知2x＋5y－3＝0，求4x·32y 的值；

(2)已知273×94＝3x，求x 的值．

21．已知A＝355，B＝444，C＝533，试比较A，B，C 的大小．

答案：

1---4 BDCD

5.a6 a4 a3

6. 8

7---13 ADCBC CB

14. 27

15. 360

16. (1) －a9 (2) (x－y)29 (3) －a9

17. (1) 解：原式＝x13

(2)解：原式＝a9n＋2

(3)解：原式＝4x8

(4) 解：原式＝3(a－b)6

18. 解：原式＝x6n－5x4n＝(x2n)3－5(x2n)2＝53－5×52＝0

19. 解：103m＋2n＝(10m)3·(10n)2＝23×32＝72

20. (1) 解：由2x＋5y－3＝0 得2x＋5y＝3，所以4x·32y＝22x·25y＝22x＋5y＝23＝8

(2) 解：x＝17

21. 解：因为A＝355＝(35)11＝24311；B＝444＝(44)11＝25611；C＝533＝(53)11＝12511，所以B＞A＞C

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