Several methods exist. For example: solve one equation for one variable, replace that variable in the other equation. (Two simultaneous equations will often have two variables each.)
The graphs of the two equations have only one intersection point.
There is no special name. Two totally unrelated equations could have the same solution(s).
simultaneous equations
Solving equations in two unknowns requires two independent equations. Since you have only one equation there is no solution.
To find the x-value where the two equations are approximately equal between -2 and -1.5, you would typically evaluate the two equations at various points in that range. By checking values or using methods such as graphing or numerical approximation (like the bisection method), you can determine the specific x-value where the equations intersect. Without specific equations provided, it's impossible to give an exact answer, but the solution lies in that interval.
equal equations.
The solution of a system of linear equations is a pair of values that make both of the equations true.
The two equations represent parallel lines.
The graphs of the two equations have only one intersection point.
If you graph the two functions defined by the two equations of the system, and their graphs are two parallel line, then the system has no solution (there is not a point of intersection).
The slopes (gradients) of the two equations are different.
There is no special name. Two totally unrelated equations could have the same solution(s).
Consistent equations are two or more equations that have the same solution.
simultaneous equations
Solving equations in two unknowns requires two independent equations. Since you have only one equation there is no solution.
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.
An independent system has one solution.