Let's plug a + 2 in for x.
[tex]f(x)=3(a+2+5)+ \frac{4}{(a+2)} [/tex]
[tex]f(x)=3a+21+ \frac{4}{a+2} [/tex]
Now here comes the hard part; we have to find the common denominator between rational expressions!
[tex]f(x)= \frac{3a}{1} + \frac{4}{a+2} +21[/tex]
[tex]f(x)= \frac{3a(a+2)}{a+2} + \frac{4}{a+2} +21[/tex]
See what I did there? Now we have common denominators, and the values are still the same ;)
[tex]f(x)= \frac{3a^2+6a}{a+2} + \frac{4}{a+2} +21[/tex]
[tex]f(x)= \frac{3a^2+6a+4}{a+2} + \frac{21(a+2)}{a+2}[/tex]
Did the same thing for 21.
[tex]f(x)= [tex]f(x)=\frac{3a^2+27a+46}{a+2}[/tex][/tex]
Here is what I got. It is always helpful to check work, however. I couldn't factor the top quadratic equation. Hope this helps!
