Answer :
You need to factor your numerator, which will give you (a + 3)(a + 4), and then divide by a + 4. You will that a + 4 cancel out in the numerator and the denominator. You are left with a + 3, which is your answer.
[tex]a^2+7a+12=a^2+3a+4a+12=a(a+3)+4(a+3)=(a+3)(a+4)[/tex]
[tex]therefore:\\\\\frac{a^2+7a+12}{a+4}=\frac{(a+3)(a+4)}{a+4}=a+3[/tex]
[tex]therefore:\\\\\frac{a^2+7a+12}{a+4}=\frac{(a+3)(a+4)}{a+4}=a+3[/tex]
