Question

5的m次方等于3,25的n次方等于4,求5的4m次方减2n次方减1次方的值.

Answer 1

5^m=3

25^n=5^(2n)=4

5^(4m-2n-1)

=5^(4m-(2n+1))

=5^(4m)/5^(2n+1)

=(5^m)^4/[5^2n*5]

=81/20