Câu trả lời:
b, = \(\frac{2\left(x+1\right)-\left(x-1\right)}{\left(x-1\right)\left(x+1\right)}.\frac{\left(x-1\right)\left(x+1\right)}{\left(x+3\right)^2}+\frac{x+1}{2\left(x+3\right)} \)
=\(\frac{x+3}{\left(x+3\right)^2}+\frac{x+1}{2\left(x+3\right)}\)
=\(\frac{1}{x+3}+\frac{x+1}{2\left(x+3\right)}\)
=\(\frac{2+x+1}{2\left(x+3\right)}=\frac{1}{2}\)