I'm taking an online "Elementary Algebra" class from my local community college. It's been a few years since I graduated high school and I've forgotten pretty much everything; including my T-84 Silver, which I never took full advantage of its potential anyway.

So I went out and got myself a new calculator, and for some reason I got the nicest one available; the TI-nspire CX CAS and I am utterly lost. Please excuse my ignorance, I'm about to ask some extremely stupid questions:

First of all, how you divide?!?! When I try, it gives me the answer as a reduced, improper fraction. How can I convert that to a decimal? Or is there a setting I can change to do it automatically.

Similarly, how do I add/subtract/multiply/divide fractions on it? To make the line between the numerator and the denominator is it just the ÷ key?

Also, I see that there is an "=" button that doesn't actually solve math problems, like the Enter button does. This leads me to believe I can enter entire equations and have the calculator solve for x. Is this true? And if so, how do I accomplish that?

Finally, will it/how do I get it to do fractional proportions? For example, what buttons would I press to solve this:

x = _ 5

9 4

I apologize for the many stupid questions, thanks in advanced for the help!