0 bình luận về “Môn Toán Lớp 8: `(x + 1)/(x^2 + x + 1)` `-` `(x – 1)/(x^2 – x + 1)` = `3/[x(x^4 + x^2 + 1)]`”

1. (x+1)/(x^2+x+1) – (x-1)/(x^2-x+1)=3/(x(x^4+x^2+1))
   ((x+1)(x^2-x+1))/((x^2+x+1)(x^2-x+1)) – ((x-1)(x^2+x+1))/((x^2-x+1) (x^2+x+1))=3/(x(x^4+x^2+1))            
   (x^3+1)/((x^2+x+1)(x^2-x+1)) – (x^3-1)/((x^2+x+1)(x^2-x+1))=3/(x(x^4+x^2+1))
   (x^3+1-(x^3-1))/((x^2+x+1)(x^2-x+1))=3/(x(x^4+x^2+1))
   (x^3+1-x^3+1)/((x^2+x+1)(x^2-x+1))=3/(x(x^4+x^2+1))
   2/((x^2+x+1)(x^2-x+1))=3/(x(x^4+x^2+1))
   (2x)/(x(x^2+x+1)(x^2-x+1))=3/(x(x^4+2x^2+1-x^2)
   (2x)/(x(x^2+x+1)(x^2-x+1))=3/(x[(x^2+1)^2-x^2]
   (2x)/(x(x^2+x+1)(x^2-x+1))=3/(x(x^2+x+1)(x^2-x+1))
   (2x)/(x(x^2+x+1)(x^2-x+1))-3/(x(x^2+x+1)(x^2-x+1))=0
   (2x-3)/(x(x^2+x+1)(x^2-x+1)=0
   2x-3=0=>x=3/2

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