分子是(8分之5+5分之8+1)*(5分之1-8分之1)的平方
1个回答

(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