1/2x+1/8x=25/54
5/8x=25/24
x=25/24×8/5
x=5/3
x÷2/7×3/4=12
x÷2/7=16
x=16×2/7
x=32/7是25/541/2x+1/8x=25/54 5/8x=25/54x=25/54×8/5x=20/27x÷2/7×3/4=12x÷2/7=16x=16×2/7x=32/74/5×2/7÷6/7×5/6[(3/5-1/3)÷4/5]÷1/84/5×2/7÷6/7×5/6=（4/5×5/6）×（2/7×7/6）=2/3×1/3=2/9[(3/5-1/3)÷4/5]÷1/8=[4/15÷4/5]÷1/8=1/3÷1/8=8/3