Question

  Hộ e 2bài vs

Answer 1

8:

ĐKXĐ: x<>1; x<>-1; x<>-1/2

a:

\(B=\dfrac{x\left(x-1\right)^2}{x^2+1}:\left[\left(\dfrac{\left(1-x\right)\left(1+x\right)}{\left(1-x\right)}+x\right)\cdot\dfrac{1+x^2-x-x^2}{1+x}\right]\)

\(=\dfrac{x\left(x-1\right)^2}{x^2+1}:\left[\left(1+x+x\right)\cdot\dfrac{1-x}{1+x}\right]\)

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

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

b: Khi x>0 thì x-1 chưa chắc lớn hơn 0

Do đó: B chưa chắc lớn hơn 0 khi x>0 đâu nha bạn