Help needed for PreCalculus Questions?

1) for grafhing any thing the easiest way is to give it a point and then join them together for example f(X)=x-3 x>5 , first for x=5 => f(x)=5-3=2 , x=6 => f(x)=6-3=3 . you have 2 point . (5,2) & (6,3) . find these points and join them .