Answer:
- the graph may be difficult to draw
- the answer may be difficult to read from the graph
Step-by-step explanation:
We assume the concern is with systems of linear equations. Systems of non-linear equations will have some of the same issues.
A system of equations is nicely solved by graphing if the graph(s) can be made easily and if the solutions can be easily read from the graph. If those conditions are not met, then solving a system graphically may not be feasible.
The attached graph shows a system of equations that would be difficult to solve graphically by hand. (A graphing calculator helps immensely.)
The system in our example is ...
We have chosen the second equation to have a slope similar to that of the first equation, so that the lines gradually come together. That makes it difficult to read the point of intersection from the graph. The second equation also has no obvious integer solutions, so graphing it in the first place can be difficult. If the solutions have a fractional part, the exact value of the fraction may be impossible to determine from the graph.
In short, ...
- creating the graph(s) may be difficult
- reading the graph with sufficient precision may be difficult
