I have noticed that most of them are simple D.E with separable variables.
first step separate the variables left the y right the x
then integrate it is not difficult
example get the second one dy/dx =6/(x^2-9)
after you separate the variables you must get dy=(6/x^2-9)dx
and after integration you will get y= ln|x-3|-ln|x+3| +C ,where c is the constant of integration...
good luck with the remaining.