Question

câu 1 cm bt sau ko phụ thuộc vào x

A:x/x-1 +x/x+1 +2-x^2/1-x^2

Answer 1

A = \(\frac{x}{x-1}+\frac{x}{x+1}+\frac{2-x^2}{1-x^2}\)

   = \(\frac{x\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}\)+ \(\frac{x\left(x-1\right)}{\left(x+1\right)\left(x-1\right)}\)\(+\frac{x^2-2}{x^2-1}\)

  = \(\frac{x\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}+\frac{x\left(x-1\right)}{\left(x+1\right)\left(x-1\right)}\)\(+\frac{x^2-2}{\left(x-1\right)\left(x+1\right)}\)

 = \(\frac{x\left(x+1\right)+x\left(x-1\right)+x^2-2}{\left(x-1\right)\left(x+1\right)}\)

=\(\frac{x^2+x+x^2-x+x^2-2}{\left(x-1\right)\left(x+1\right)}\)

 =\(\frac{3x^2-2}{\left(x-1\right)\left(x+1\right)}\)

cậu xem lại đề nha