Làm
Với x khác 1, -1 ta có:
Q=\(\frac{x+3}{x+1}-\frac{2x-1}{x-1}-\frac{x-3}{\left(x-1\right)\left(x+1\right)}\)
Q=\(\frac{\left(x+3\right)\left(x-1\right)}{\left(x-1\right)\left(x+1\right)}-\frac{\left(2x-1\right)\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}-\frac{x-3}{\left(x-1\right)\left(x+1\right)}\)
Q=\(\frac{x^2+2x-3-2x^2-x+1-x+3}{\left(x-1\right)\left(x+1\right)}\)
Q=\(\frac{-x^2+1}{\left(x-1\right)\left(x+1\right)}\)
Q=\(\frac{\left(1-x\right)\left(1+x\right)}{\left(x-1\right)\left(x+1\right)}=-1\)
Vậy......