求教两道分式题!请给出演算过程!……
1个回答

(x+3)/(x+2)+(x+5)/(x+4)=(x+7)/(x+6)+(x+9)/(x+8)

(x+5)/(x+4)-(x+7)/(x+6)=(x+9)/(x+8)-(x+3)/(x+2)

(x²+11x+30-x²-11x-28)/(x+4)(x+6)=(x²+11x+18-x²-11x-24)/(x+8)(x+2)

6/(x²+10x+24)=6/(x²+10x+16)

x²+10x+24=x²+10x+16

∴原方程无解

4/x+1/y=2,xy=-1,

∴4y+x=2xy=-2

(4y-x)/(x-2y)÷[x+2y-12y²/(x-2y)]

=(4y-x)/(x-2y)÷(x²-4y²-12y²)/(x-2y)

=(4y-x)/(x²-16y²)

=(4y-x)/(x-4y)(x+4y)

=1/(x+4y)

=-1/2

=1/(x+4y)

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