[tex]\lim\limits_{x \to \infty}\dfrac{9x^4+3}{4x^4}=\lim\limits_{x \to \infty}\dfrac{x^4\cdot\left(9+\dfrac{3}{x^4\right)}}{4x^4}=\lim\limits_{x \to \infty}\dfrac{9+\dfrac{3}{x^4}}{4}=\dfrac{9+0}{4}=\dfrac{9}4.\\\\I\;used\;\lim\limits_{x\to\infty}\dfrac{3}{x^4}=0.[/tex]
Green eyes.