prove that A-(A intersection B)= A-B

Now A-B is the difference of the sets A and B.If A and B are two sets then their difference A-B is the set of all those elements of A which do not belong to B.
$A\cap B$ is the intersection of the two sets A and B  which represents the set of all elements common to both A and B 

Now from the figure , it is clear that (A-B) and ($A\cap B$) are disjoint sets and their union is A
$\therefore$(A-B) +($A\cap B$) = A
$\Rightarrow$A-($A\cap B$) = (A-B) proved