试题
题目:
(1)已知a
m
=2,a
n
=3,求a
3m+2n
的值;
(2)已知e
3
=m,e
5
=n,试用含m,n的代数式表示e
1如
.
答案
解:(f)∵a
m
=p,a
n
=3,
∴a
3m+pn
=a
3m
·a
pn
=(a
m
)
3
·(a
n
)
p
=p
3
×3
p
=7p;
(p)∵x
3
=m,x
5
=n,
∴x
fh
=(x
3
)
3
·x
5
=m
3
n.
解:(f)∵a
m
=p,a
n
=3,
∴a
3m+pn
=a
3m
·a
pn
=(a
m
)
3
·(a
n
)
p
=p
3
×3
p
=7p;
(p)∵x
3
=m,x
5
=n,
∴x
fh
=(x
3
)
3
·x
5
=m
3
n.
考点梳理
考点
分析
点评
幂的乘方与积的乘方;同底数幂的乘法.
(1)由a
3m+2n
=a
3m
·a
2n
=(a
m
)
3
·(a
n
)
2
,即可求得答案;
(2)由x
14
=(x
3
)
3
·x
5
,即可求得答案.
此题考查了同底数幂的乘法与幂的乘方.此题难度适中,注意掌握公式的逆运算是关键.
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