The value of the function f(x) is −7 when x is 4 and is −13 when x is −6. The value of the function g(x) is 17 when x is −3 and is −3 when x is 5. If p represents the slope of f(x) and q represents the slope of g(x), when is the value of pq?
-2/3
2/3
3/2
-3/2