=========================Cramer_Rule==========================

Say you have two x values you wish to find. If you can write two 
independent equations for in the following format, you can use a 
simple little method to solve for the unknowns. This assumes you 
have known values for everthing but the x values. 
                      
y_1 = A1*x_1 +A2*x_2   
y_2 = A3*x_1 +A4*x_2   
  
The method involves matrixes and determinats as is show below.  

 x_1 = | y_1  A2 |  / | A1  A2 |
       | y_2  A4 | /  | A3  A4 |

 x_2 = | A1  y_1 |  /
       | A3  y_2 | / ( A1*A4 - A2*A3 )

The answer is just as follows. 

 x_1 = (y_1*A4  -A2*y_2 )/( A1*A4 - A2*A3 )
 x_2 = (y_2*A1  -A3*y_1 )/( A1*A4 - A2*A3 )