Respuesta :

The correct answer for the exercise shown above is:

 a=-4

 The explanation is shown below:

 1. You have the following expresssion given in the problem above:

 a+6/a+4

 2. By definition, the nonpermissible replacement for a is the value that make the denominator equal to zero.

 3. Keeping this on mind, you have:

 a+4=0
 a=-4

 a+6/a+4=-4+6/-4+4=2/0

 Therefore, as you can see, the answer is a=-4.