已知3的2m次方=5,3n=10求9的m-n次方,9的2m-n_数学解答

已知3的2m次方=5,3n=10求9的m-n次方,9的2m-n

人气：379 ℃　时间：2019-10-17 10:44:43

解答

9^(m-n)
=9^m/9^n
=3^2m/(3^n)^2
=5/10^2
=5/100
=0.05
9^(2m-n)
=9^2m/9^n
=(3^2m)^2/(3^n)^2
=5^2/10^2
=25/100
=0.25