a) \(\frac{1}{x+3}+\frac{x}{x^2-6x+9}\left(x\ne\pm3\right)\)
\(=\frac{1}{x+3}+\frac{x}{\left(x-3\right)^2}=\frac{\left(x-3\right)^2}{\left(x+3\right)\left(x-3\right)^2}+\frac{x^2+3x}{\left(x+3\right)\left(x-3\right)^2}\)
\(=\frac{x^2-6x+9-x^2+3x}{\left(x-3\right)^2\left(x+3\right)}=\frac{-3x+9}{\left(x-3\right)^2\left(x+3\right)}=\frac{-3\left(x-3\right)}{\left(x-3\right)^2\left(x+3\right)}=\frac{-3}{\left(x-3\right)\left(x+3\right)}\)
anhdun_•Ŧ๏áйツɦọς• giải a r nha , tớ giải b+c cho
\(b,\frac{2x}{x^2-9}-\frac{x-1}{x+3}\)
\(\frac{2x}{x^2-3^2}-\frac{x-1}{x+3}\)
\(\frac{2x}{\left(x+3\right)\left(x-3\right)}-\frac{x-1}{x+3}\)
\(\frac{2x-\left(x-1\right)\left(x-3\right)}{\left(x+3\right)\left(x-3\right)}\)
\(\frac{2x-x^2+3x+x-3}{\left(x+3\right)\left(x-3\right)}\)
\(\frac{\left(2x+3x+x\right)-x^2-3}{\left(x+3\right)\left(x-3\right)}\)
\(\frac{6x-x^2-3}{\left(x+3\right)\left(x-3\right)}\)
\(c,\frac{2x+1}{x-2}.\frac{2-x}{2x+1}\)
\(\frac{1}{x-2}\left(2-x\right)\)
\(\frac{2-x}{x-2}\)
\(-\frac{-2+x}{x-2}=-1\)
