Math Proof

Okay everybody, prove the following:

Theorem 4.3:

Given distinct points P and Q, a segment AB , and points R
and S such that R and S are on −! PQ , PR = AB , and PS = AB , then
R = S.

P 6= Q & R, S are on −! PQ & PR = AB & PS = AB ! R = S.

Just kidding! I stare at this stuff all day long.....no wonder I go nuts!