Question

thực hiện phép tính

a) \(\dfrac{x-1}{x+1}\)-\(\dfrac{x+1}{x-1}\)+\(\dfrac{4}{x^2-1}\)

b) \(\dfrac{x^3y+xy^3}{x^4y}\):(x²+y²)

Answer 1

a: \(=\dfrac{x^2-2x+1-x^2-2x-1+4}{\left(x-1\right)\left(x+1\right)}=\dfrac{-4\left(x-1\right)}{\left(x-1\right)\left(x+1\right)}=\dfrac{-4}{x+1}\)

b: \(=\dfrac{xy\left(x^2+y^2\right)}{x^4y\left(x^2+y^2\right)}=\dfrac{1}{x^3}\)