\(f(x)=-\mathrm{e}^{3 x+4}(x-5) \)
f´(x)=-\( e^{3x+4} \)*3*(x-5)-\( e^{3x+4} \)
-\( e^{3x+4} \)*[3*(x-5)+1]=0
3*(x-5)+1=0
x=\( \frac{14}{3} \)
f´(x)=-[\( e^{3x+4} \)*(3x-14)]
f´´(x)=-[\( e^{3x+4} \)*3*(3x-14)+\( e^{3x+4} \)*3]
f´´(\( \frac{14}{3} \))=-[0+\( e^{18} \)*3]<0 Maximum