  Systems of equations and inequalities: Graphical and analytical relationships 50     SysGraph     In each problem, two equations are required to describe related events. The student then uses the trace function to find the intersection of some aspect of the events. Use the up arrow to move the cursor from one line to the other. The trace readout can be used to minimize the difference between the two Y values The program takes into account the fact that the answers, being graphical solutions will be approximate. The  ^  can be used to correct an entry or to return to the trace function for the intersection. 51     SysSubst     The student is presented with 2 equations in X and Y and asked to find the solution. The more difficult situations are left for solving by combination. 52     SysComb1     The equations in this program are slightly more difficult and are better solved by combination. 53     SysComb2     The equations in this program require that at least one of them be multiplied by some number in order to eliminate a variable by combination. 54     SysWordP     This program treats only one distance, rate and time problem.  There are four steps in its solution. The problem is repeated four times, using different values.  It is not necessary to calculate the final answer to the last two questions. The program will accept an answer such as  40(25/24) + 45. 55     SysSpecl     The systems of equations in this program are most easily solved by combination. For those systems which are inconsistent and have no solution, respond with the letter  N.  For those systems which involve dependent equations, and therefore have an infinity of solutions, respond with the letter  I. 56     SysIneql     In each problem, two inequalities are presented and their graphs are displayed. The student is asked to identify whether the solution set lies in the region identified by the letter  A,  B,  C,  or  D.  In a few instances, either the region B, or the region  D may be off of the screen, but its location is still clear. <<>> 