It depends on what the actual graph of the function looks like. If it clearly intersects the [katex] x [/katex]-axis and the values by which the graph intersects the [katex] x [/katex]-axis are easy to determine, then using the graph is a good strategy to use. However, if the graph of the function does not intersect the [katex] x [/katex]-axis or it intersects the [katex] x [/katex]-axis not at a whole number, then using a different strategy would be more effective.