Using the laws of Boolean Algebra:

1. Factor out the common term $A$: $A+AB=A\cdot (1+B)$
2. According to the Annulment Law (or Identity Law for OR), $(1+extanything)=1$: $1+B=1$
3. Therefore: $A\cdot (1)=A$ This is known as the Absorption Law. Intuitively, if $A$ is true, the whole expression is true regardless of $B$. If $A$ is false, both terms are false, so the whole expression is false. Thus the result is simply $A$.