（5/8+8/5+1)*(1/5-1/8)^2/[(5/8)^2+(8/5)^2-5/8-8/5]
=（5/8+8/5+1)*(1/5-1/8)^2/[(5/8)^2+(8/5)^2+2-2-5/8-8/5]
=（5/8+8/5+1)*(1/5-1/8)^2/[(5/8+8/5)^2-(5/8+8/5)-2]
=（5/8+8/5+1)*(1/5-1/8)^2/[(5/8+8/5-2)(5/8+8/5+1)]
=(1/5-1/8)^2/(5/8+8/5-2)
=(1/5-1/8)^2/(5/8-1+8/5-1)
=(1/5-1/8)^2/(8/5-1+5/8-1)
=(1/5-1/8)^2/(3/5-3/8)
=(1/5-1/8)^2/[3*(1/5-1/8)]
=(1/5-1/8)/3
=[(8-5)/40]/3
=3/40*1/3
=1/40