Answer:
If each linear function is given as a set of two ordered pairs, you need to use those points to find the equation of each line, and then solve the system of equations.
For example:
Let's say that f(x) has the following ordered pais: (a, b) and (c, d) and g(x) has the following ordered pais: (e, f) and (g, h). We know that the general equation of a line is the following:
(y - yo) = m(x-xo), where 'm' represents the slope and (xo, yo) any point from the line.
The slope will be given by: (y1 - yo)/(x1 - x0).
For example, the equation of the line of f(x) is:
f(x) = (y - b) = [(d - b)/(c - a)](x-a)
You do the same for the function g(x), and then you are all set to solve the system of equations!