①若2^x=3,2^y=5,则2^2x-y=?②（-m²n³）^6÷（m²n³）

2^x=3,2^y=5
2^(2x)=(2^x)^2=3^2=9
2^(2x-y)
=2^(2x)÷2^y
=9/5
(2)
（-m²n³）^6÷（m²n³）^2
=（m²n³）^6÷（m²n³）^2
=（m²n³）^(6-2)
=（m²n³）^4
=m^8n^12
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