Given:

f(x)=7x+4x+9x\displaystyle {f{{\left({x}\right)}}}=-{7}{x}+{4}\sqrt{{{x}}}+\frac{{9}}{{x}} 

find:

(a) f(x)=\displaystyle {f}'{\left({x}\right)}=   

(b)  the rate of change  with respect to x\displaystyle {x} when x=4\displaystyle {x}={4}.  

(c)  the relative rate of change with respect to x\displaystyle {x} when x=4\displaystyle {x}={4}.  

(d)  the percentage rate of change with respect to x\displaystyle {x} when x=4\displaystyle {x}={4}.