Question

Giúp e với ạ   

Answer 1

a: ĐKXĐ: x<>2

\(\dfrac{2x^2-1}{x-2}+\dfrac{-x^2-3}{x-2}\)

\(=\dfrac{2x^2-1-x^2-3}{x-2}=\dfrac{x^2-4}{x-2}\)

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

b: ĐKXĐ: \(x\ne\pm y\)

\(\dfrac{x}{x+y}+\dfrac{y}{x-y}\)

\(=\dfrac{x\left(x-y\right)+y\left(x+y\right)}{\left(x+y\right)\left(x-y\right)}\)

\(=\dfrac{x^2-xy+xy+y^2}{x^2-y^2}=\dfrac{x^2+y^2}{x^2-y^2}\)