When x

When x> is =-34/23, f(x) is a decreasing function.

If f(x) is increasing function and g(x) is a decreasing function, then f(x)+g(x) may be increasing function, a decreasing function or a fixed value function.

For example:

1, f(x)=2x g(x)=-x, then f(x)+g(x)=x is increasing function.

2. If f (x) = x g (x) =-2x, then f(x)+g(x)=-x is a subtraction function.

3.f(x)=x g(x)=-x+2, then f(x)+g(x)=2, which is a fixed value function.