Respuesta :
[tex]\bf 14^{x+3}=21\implies log(14^{x+3})=log(21)\implies (x+3)log(14)=log(21)
\\\\\\
x+3=\cfrac{log(21)}{log(14)}\implies x=\cfrac{log(21)}{log(14)}-3[/tex]
and surely you'd know what that is.
and surely you'd know what that is.