y=√(x-1/2)+√(1/2-x)+1/2
x-1/2≥0,x≥1/2
1/2-x≥0,1/2≥x
所以,x=1/2
y=0+0+1/2=1/2
5x+|2y-1|-√(y^-2y+1)
=5/2+(2*1/2-1|+√(1/4-1+1)
=5/2+0+1/2
=3