x =0 không là nghiệm
chia 2 vế cho x^2
[tex]144x^2 +1512x +5309 +\frac{7560}{x}+\frac{3600}{x^2}=0 \\\Leftrightarrow 144(x^2 +\frac{25}{x^2})+1512(x+\frac{5}{x})+5309=0\\\Leftrightarrow 144[(x+\frac{5}{x})^2-10]+1512(x+\frac{5}{x})+5309=0\\\Leftrightarrow 144(t^2-10)+1512t+5390=0[/tex]