Answer:
x + 11
Step-by-step explanation:
Substitution!
Since you're trying to find f(x+10), you would replace each x in the equation (in this case only one) with x+10.
So instead of
[tex]x+1[/tex]
it would be
[tex](x+10)+1 = x + 10 + 1 = x + 11[/tex]
