(0.9^m*0.8^n)÷(0.9^n*0.8^m)
=0.9^(m-n)/0.8^(m-n)
=(9/8)^(m-n)
∵m>n
∴m-n>0
∴(9/8)^(m-n)>1
∴0.9^m*0.8^n > 0.9^n*0.8^m