Cộng, trừ các phân thức sau: [x+1 / 2x-2 + 3/x^2 -1 - x+3/2x + 2]. 4x^2 -4/5

* Hướng dẫn giải

$\begin{array}{l}\left[\frac{\mathrm{x}+1}{2\mathrm{x}-2}+\frac{3}{{\mathrm{x}}^2-1}-\frac{\mathrm{x}+3}{2\mathrm{x}+2}\right].\frac{4{\mathrm{x}}^2-4}{5}\\ =\left[\frac{\mathrm{x}+1}{2\left(\mathrm{x}-1\right)}+\frac{3}{\left(\mathrm{x}-1\right)\left(\mathrm{x}+1\right)}-\frac{\mathrm{x}+3}{2\left(\mathrm{x}+1\right)}\right].\frac{4\left({\mathrm{x}}^2-1\right)}{5}\\ =\frac{{\mathrm{x}}^2+2\mathrm{x}+1+6-{\mathrm{x}}^2-2\mathrm{x}+3}{2\left(\mathrm{x}-1\right)\left(\mathrm{x}+1\right)}.\frac{4\left(\mathrm{x}-1\right)\left(\mathrm{x}+1\right)}{5}\\ =\frac{10.4}{2.5}=4\end{array}$