Considering High School level question, answer can be written as:
A system of 2 linear equations is [two] dimensional. It is a graph of [two] lines. The solutions can be [unique] solution if the graph intersects. [No] solution if the lines are parallel - meaning they have the same slope, or [Infinitely many] solutions if they are the same line.
Explanation:
when two lines are drawn on a two-dimensional plane then there are only three possible cases:
Case1: lines will intersect
In that case you will get a unique solution at the intersection point.
Case2: lines are parallel but don't touch each other
In that case there will be no point which lies on both lines so No solution.
Case3: lines are overlapping.
In that case all the points lies on both lines so infinitely many solutions.
