Let f(x)=3x+1\displaystyle {f{{\left({x}\right)}}}=-{3}{x}+{1}.

According to the definition,

f(x)=limh0\displaystyle {f}'{\left({x}\right)}=\lim_{{{h}\to{0}}} (enter the limit in reduced form)

 

f(x)=\displaystyle {f}'{\left({x}\right)}= (enter the limit)