Answer:
[tex]f(f(3))=156[/tex]
Step-by-step explanation:
we are given
[tex]f(x)=x^2+x[/tex]
We can replace x
[tex]f(f(x))=(f(x))^2+f(x)[/tex]
now, we can replace
[tex]f(f(x))=(x^2+x)^2+x^2+x[/tex]
now, we can plug x=3
and we get
[tex]f(f(3))=(3^2+3)^2+3^2+3[/tex]
we get
[tex]f(f(3))=(9+3)^2+12[/tex]
[tex]f(f(3))=(12)^2+12[/tex]
[tex]f(f(3))=144+12[/tex]
[tex]f(f(3))=156[/tex]
So,
[tex]f(f(3))=156[/tex]