Question

giúp t câu c với 

 

Answer 1

\(P=\dfrac{x+3}{x-2}+\dfrac{x-3}{x+2}-\dfrac{2x^2+3x+6}{x^2-4}\)        \(Đk:x\ne\pm2\)

    \(=\dfrac{\left(x+3\right)\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}+\dfrac{\left(x-3\right)\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}-\dfrac{2x^2+3x+6}{x^2-4}\)

    \(=\dfrac{x^2+5x+6+x^2-5x+6-2x^2-3x-6}{x^2-4}\)

    \(=\dfrac{-3x}{x^2-4}\)

Thay \(x=3\left(tmđkx\ne\pm2\right)\) vào P ta đc:

\(P=\dfrac{-3\cdot3}{3^2-4}=-\dfrac{9}{5}\)