1 、x+y=8 xy=6 求x²+3xy+2y²/x²y+2xy²

1 、x+y=8 xy=6 求x²+3xy+2y²/x²y+2xy²的值.
x²+3xy+2y²/x²y+2xy²
=(x+2y)(x+y)/xy(x+2y)
=(x+y)/xy x+y=8 xy=6
=8/6
=4/3
2、3/a=4/b=5/c,求分式 ab-bc+ac/a²+b²+c²的值
∵3/a=4/b=5/c,
∴b=4a/3
c=5a/3
∴ab-bc+ac/a²+b²+c²
=(a*4a/3-4a/3*5a/3+a*5a/3)/(a²+16a²/9+25a²/9)
=(4a²/3-20a²/9+5a²/3)/(50a²/9)
=(27a²/9-20a²/9)/(50a²/9)
=(7a²/9)/(50a²/9)
=7/50