) Consider f(x)=ax+xln(bx) for a>0, b>1, and x>1.
Find f′(x): f′(x)= 
Based on your expression for f′(x), is f(x) increasing or decreasing? (Enter increasing or decreasing.) 
(Be sure that you can see why this is true for all values x>1.)
Find f′′(x): f′′(x)= 
Based on your expression for f′′(x), is f(x) concave up or concave down? (Enter up or down.) 
(Be sure that you can see why this is true for all values x>1.)