You can use the Polynomial Root Finder Application to:
Select the application.  
This is the menu for the 

The Poly Root Finder main screen is displayed. Here you will enter the information about the polynomial and select options for your answer. 

Press the key. To access the menu at the bottom of the screen, use the graphing keys below the option. 

We will now find the roots 

The solution is shown. To change the coefficients to solve another equation, just select COEF and enter another set of coefficients. 

To change to a different degree polynomial, go back to the MODE menu and select another order. 

Now we will solve a 4th degree equation with the coefficients shown. 

All of these solutions are real numbers. 

You can select COEF and change the coefficients. Note that the last two solutions are shown in the complex form. They are not real number solutions. 

Selecting STO will allow to choose how you want to store the solutions or the polynomial. You can store the solutions or coefficients to a list. Or, you can store the polynomial to the graph editor and then graph the polynomial. 
You can use the Simultaneous Equations Solver Application to:
Select the application.  
This is the menu for the 

This is the main menu for the simultaneous equation solver. We will solve a 3 by 3 equation. 

This is the system we will solve. 

From the menu, select 

Enter the coefficients. 

Solve the system.  
If you want to store the matrix, press STO. You can store the system or the matrix. 