It means you performed an operation on the system which was not invertible. This allowed you to come to a solution but that solution is not correct since it is not a proper biconditional relations. That is, you can solve it in terms of p->q but not the reverse (since the inverse operation is not possible).
extraneous solution. or the lines do not intersect. There is no common point (solution) for the system of equation.
isolate
there is no linear equations that has no solution every problem has a solution
A system of equations may have any amount of solutions. If the equations are linear, the system will have either no solution, one solution, or an infinite number of solutions. If the equations are linear AND there are as many equations as variables, AND they are independent, the system will have exactly one solution.
overlap
extraneous solution. or the lines do not intersect. There is no common point (solution) for the system of equation.
2
In general, a system of non-linear equations cannot be solved by substitutions.
isolate
Isolating a variable in one of the equations.
A system of equations means that there are more than one equations. The answer depends on the exact function(s).
there is no linear equations that has no solution every problem has a solution
A system of equations with exactly one solution intersects at a singular point, and none of the equations in the system (if lines) are parallel.
A system of equations may have any amount of solutions. If the equations are linear, the system will have either no solution, one solution, or an infinite number of solutions. If the equations are linear AND there are as many equations as variables, AND they are independent, the system will have exactly one solution.
None, one or many - including infinitely many.
The solution of a system of linear equations is a pair of values that make both of the equations true.
A system of equations will have no solutions if the line they represent are parallel. Remember that the solution of a system of equations is physically represented by the intersection point of the two lines. If the lines don't intersect (parallel) then there can be no solution.