Find the intervals on which for) is increasing and the intervals on which flx) is decreasing. Then sketch the graph. Add horizontal tangent lines. f(x}=6+8x-x2 Select the correct choice below and, it necessary, fill in the answer box to complete your choice. 0 A. The function is increasing on (T yes your answer using interval notation. Use a comma to separate answers as needed] 0 8. There is no solution