Respuesta :
f(9) means let x=9 and substitute into f(x)
f(9) = 9^2 +10
f(9) = 81+10
f(9) = 91
it means the value of the function when x=9
just replace every x with a 9 and remember order of operations
[tex]f(x)=x^2+10[/tex]
[tex]f(9)=(9)^2+10[/tex]
[tex]f(9)=81+10[/tex]
[tex]f(9)=91[/tex]