[tex]\frac{6x}{x^{4} + 5}[/tex]
Let's plug in 2 anywhere that we see an [tex]x[/tex]:
[tex]\frac{6(2)}{(2)^{4} + 5}[/tex]
[tex]\frac{12}{16 + 5}[/tex]
[tex]\frac{12}{21}[/tex]
Both the numerator and denominator are divisible by 3, so we can divide 3 out of each to get the final answer:
[tex]\frac{3 * 4}{3 * 7}[/tex]
[tex]\frac{4}{7}[/tex]