Namir, the non-CAS version does not solve systems of equations like the CAS version does. The non-CAS version does have the RREF function, so I guess that could be used to solve a system of equations if you translate the coefficients to the matrix. But the CAS version has specific templates for solving systems of equations. I have not used them (don't have the CAS version yet), but I would imagine you just type your equations in as-is and tell it to find the values of your variables.

To find zeroes of a function, or maxima or minima, on the non-CAS version I think you have to graph the equation on the geometry screen and then observe where the function crosses the x-axis (for zeroes), and for maxima and minima you do a Trace near that point on the graph and when you hit the maximum point on the curve a M is displayed next to the graph, and when you hit the minimum point a lower-case m is displayed (there are no CALC...MAX...MIN functions like on the TI-83 series, unfortunately). On the CAS version, there are specific functions for fmin, fmax, and zeroes, and I imagine you don't even need the graph for those, you just type in the equation and specify an interval and it gives you the answer.

You are right, the spreadsheet function is nicely integrated into the rest of the system, even to the point that it will populate a column with values while you drag part of a graph, then use the generated values in the column for a separate scatter-plot. Very nicely done.

I'm going to get the CAS version when it is available. At the conference I went to last month they estimated October availability for the CAS version, although it seems some companies are offering it now.