A linear equation in 2 variables does not have a single number as a solution.
It has a SOLUTION Set containing an unlimited number of pairs of values for the 2 variables respectively.
A linear equation in 2 variables represents a straight line on a graph.
Every single pair of values in the solution set of the linear equation represents a point on the line and vice versa.
Solving for a system of 2 equations means finding a single pair of values for x and y such that both these equations are satisfied.
The method of solving by substitution, involves substituting for one variable
and then , reducing system to just an equation in one variable.
The method of solving by Elimination involves adding or subtracting one of the two equations,
and then, elimination of one out of the 2 variables.
The method of solving by graphs involves identifying the point of intersection between the lines
and reading out x and y coordinates as x and y values of solution.
A system of linear equations is said to have a unique solution if there is only 1 unique pair of values of x and y which satisfy both equations in the system.
Graphically, the lines representing the equations intersect at one point.
There are cases where there are no values of x and y that can satisfy both equations in the system simultaneously. We say that there is no solution to the system
Graphically, the lines representing these equations are parallel to each other.