Respuesta :

TPS00

[tex]f(x) = {x}^{2} + 9 \\ \\ f(x + 3) = {(x + 3)}^{2} + 9 [/tex]

[tex]f(x + 3) =( {x}^{2} + 6x + 9) + 9 \\ \\ f(x + 3) = {x}^{2} + 6x + 18[/tex]

[tex]thus \boxed{ \red{f(x + 3) = {x}^{2} + 6x + 18 }}[/tex]