71If one is increasing then other must be decreasing.
Since, they are linear you may assume it to be f(x) = ax+b.
Now, In case of it being increasing, we have x = -1 , f(-1)=-a+b=0 and x = 1, f(1) = a+b = 3.
Now eliminate a,b to get the f(x). Similarly with g(x), the other function, you put x = -1 and g(-1) = 3
Solve to get answer.
