x1+x2=2m
x1*x2=n^2/4
(x1+x2)^2=x1^2+x2^2+2x1x2=4m^2
x1^2+x2^2=4m^2- n^2/2
│x1-x2│=8 (两边平方)
x1^2+x2^2-2x1x2=64
4m^2- n^2/2- n^2/2=64
4m^2-n^2=64 (1)
三角形的高为:h=√m^2-(n/2)^2=√(4m^2-n^2)/4=√64/4=4
S=1/2*4*n=12 n=6代入(1)
得到m=5
腰长为5,底边长为6