Answer:
[tex]a^{2} -1[/tex]
Step-by-step explanation:
The LCD, or the lowest common denominator would be [tex]a^2-1[/tex]
If we multiply the second term [tex]\frac{1}{a+1}[/tex] by [tex]\frac{a-1}{a-1}[/tex] ([tex]\frac{a-1}{a-1}[/tex] is equivalent to 1, so we can do this,) we can see that the denominator would become the same as the first term [tex]\frac{1}{a^2-1}[/tex] by difference of squares. So that creates an LCD of [tex]a^2-1[/tex]
