初二上学期关于幂的乘方的题
1.若9的m+1次方-3的2m次方=72,求m的值(有计算过程)
2.已知2的a次方=m,2的b次方=n,求2的2a+3b次方的值
怎样求出来的需要讲解下啊...要不然就没意义了撒
人气:238 ℃ 时间:2020-05-21 08:09:55
解答
9^(m+1)-3^2m=72
9^(m+1)-9^m=72
(9-1)*9^m=72
8*9^m=72
m=1
2^a=m
2^b=n
2^(2a+3b)=m^2*n^3
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