Question

helpppppppppppppppp! Bài này cần ĐKXĐ ko ạ

Answer 1

ĐKXĐ:\(x\ne\pm2\)

\(\dfrac{x+1}{x-2}-\dfrac{5}{2+x}=\dfrac{12}{x^2-4}+1\\ \Leftrightarrow\dfrac{\left(x+1\right)\left(x+2\right)}{\left(x+2\right)\left(x-2\right)}-\dfrac{5\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}-\dfrac{12}{\left(x-2\right)\left(x+2\right)}-\dfrac{\left(x-2\right)\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}=0\\ \Leftrightarrow\dfrac{x^2+3x+2-5x+10-12-x^2+4}{\left(x-2\right)\left(x+2\right)}=0\)

\(\Rightarrow-2x+4=0\\ \Leftrightarrow x=2\left(ktm\right)\)

Answer 2

\(\Rightarrow x^2+3x+2-5x+10=12+x^2-4\)

\(\Leftrightarrow-2x+12=8\Leftrightarrow x=2\left(ktm\right)\)

pt vô nghiệm