well, when it comes to graphing an inequality, and you need to know whether the line is solid or dashed, look at the inequality sign..... (i do not remember that exact terms) anyway, if it is JUST > or < then it is dashed, that is because you are not including that number, just any number greater than or less than it...
however, if it is Greater than or Equal to
or
less than or equal to
where these two are including that # by having the "or equal to", it will be solid for it is INCLUDING what ever # we are using...
for example
y > 3 will be dashed
where as y is greater than or equal to 3 will be solid since the y could be 3
i cant really explain this well... but i hope i made it somewhat clear