Take a look at this system of 2 equations,
3x plus 2y equals 6 and
6x plus 4y equals 6
If we are trying to solve this system by the method of elimination, we multiply the first equation by 2 and subtract the second from the first,
Which gives on the left hand side
6x minus 6x plus 4y minus 4y which is 0
And on the right hand side
12 minus 6 which equals 6
Not only do the left hand side and right hand side NOT match, but we have lost all the variable terms x and y in the process. We eliminated x and y.
In fact, the same problem is encountered when we try to solve by substitution.
The reason for this is that there is not one single pair of values of x and y that satisfy both these equations simultaneously.
Let’s look at the lines represented by these equations to see if we can understand the reason for this.
As you can see, the lines for the two equations are parallel to each other. This means that they would never intersect ever and thus there would be no point that would lie on BOTH lines at the same time.
This is exactly what it means to say that there is no solution pair that satisfies both the equations at the same time.