helpppppppp will mark brainlest

Answer:
-8
Step-by-step explanation:
what do you think, when you look at the examples given in the problem definition ?
don't you see the pattern, that f(x) = x+2 ?
f(1) = 1+2 = 3
f(2) = 2+2 = 4
f(3) = 3+2 = 5
so, if we follow this assumption, then
f(-10) = -10 + 2 = -8