Answer:
X-coordinate
Explanation:
The problem statement assumes you want to solve ...
f(x) = g(x)
by writing the system of equations ...
y = f(x)
y = g(x)
The solution will be points of intersection (x, y). The value of x is what is of interest in each case, since that is the solution to f(x) = g(x). That is, the solution is the X-coordinate of each intersection.