This is an interesting problem.
But first, let us define what are the three possible cases :
A system of linear equations : a system of equation is when you have two equations with the same unknown variables, that you need to solve both together. Example : "x+y = - 7 AND x + y = - 4" are two equations that form a system of equation.
Plus they are linear, a linear equation is simply an equation of the form : y = ax + b where a and b are real numbers.
Here for example x + y = - 7 is a linear equation. Because y = 1 × x - 7
where a = 1 and b = - 7.
Consistent Dependent : A system of equation is consistent Dependant when it has an infinite number of solutions.
When this is the case, the graphs of the lines in the system are the same, meaning the equations in the system represent the same line.
Consistent Independent : A system of equation is consistent Dependant when it has exactly one solution.
When this is the case, the graphs of the lines in the system cross at exactly one point.
Inconsistent : A system of equation is Inconsistent if it haas no solutions.
When this is the case, the graphs of the lines in the system do not intersect, meaning they are parallel.
Now, with those definitions above, we can work on our problem :
1. x + y = - 7 and x + y = - 4
Look at the picture attached the lines are parallel to each other so here the answer is Inconsistent
2. Same line : consistent dependent
3. Parallel Lines : Inconsistent
4. Lines cross at exactly one point :Consistent Independent
5. Lines cross at exactly one point : Consistent Independent.
You can see the graph of each systems in the pictures attached below.
Good luck, you will succeed :)
