\(\left(\dfrac{x}{x^2-25}-\dfrac{x-5}{x^2+5x}\right):\dfrac{2x-5}{x^2+5x}+\dfrac{x}{5-x}\left(đk:x\ne5,x\ne-5,x\ne0\right)\)
\(=\left(\dfrac{x^2-\left(x-5\right)^2}{x\left(x-5\right)\left(x+5\right)}\right).\dfrac{x\left(x+5\right)}{2x-5}+\dfrac{x}{5-x}\)
\(=\dfrac{x^2-x^2+10x-25}{x\left(x-5\right)\left(x+5\right)}.\dfrac{x\left(x+5\right)}{2x-5}+\dfrac{x}{5-x}\)
\(=\dfrac{5\left(2x-5\right)}{x\left(x-5\right)\left(x+5\right)}.\dfrac{x\left(x+5\right)}{2x-5}+\dfrac{x}{5-x}\)
\(=\dfrac{5}{x-5}+\dfrac{x}{5-x}=\dfrac{5-x}{x-5}=-1\)
Đúng 1
Bình luận (0)