a,1/x^2+5x+4+1/x^2+11x+28+1/x^2+17x+70=3/4x-2 b,2/3x^-4x+1+13/3x^2+2x+1=6/x c,/3x-1/+2=3x+4 d,/x-1/+/x+2/-2/x-3/=2005

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