2a=16,a=8,设方程为：x^2/64-y^2/b^2=1,
e=c/a=5/4,c=5a/4,b^2=c^2-a^2=25a^2/16-a^2=9a^2/16=36,
∴双曲线方程：x^2/64-y^2/36=1,
∴渐近线方程为：y=±3x/4.