Tìm x,biết: x+2/x+6=3/x+6

* Hướng dẫn giải

$\frac{x+2}{x+6}=\frac{3}{x+1}\Rightarrow \left(x+2\right)\left(x+1\right)=3\left(x+6\right)\Rightarrow x^2+3x+2=3x+18\Rightarrow x^2=16\Rightarrow x=\pm 4$