What value of m does the graph y = 18x2 + mx + 2 have exactly one x-intercept?

To get the graph to have one x-intercept, we must find the m value where the discriminant of the equation will equal 0.

The discriminant for a graph with one x-intercept is found with the following formula:



Plug in the values of the equation into this formula:





Add 144 to both sides:



Square root both sides to get m by itself:




In order for the graph to have one x-intercept, m must equal -12 or 12.