已知xa=3,xb=5,则x3a-2b=_.
问题描述:
已知xa=3,xb=5,则x3a-2b=______.
答
∵xa=3,xb=5,
∴x3a-2b=(xa)3÷(xb)2,
=33÷52,
=
.27 25
故填
.27 25