I'm confused. it's finding a function

Easy, that is the slope from (2,f(2)) to (3,f(3))

remember that the slope between the points (x1,y1) and (x2,y2) is
(y2-y1)/(x2-x1)

find f(2) and f(3)
f(2)=2²+6(2)+5=4+12+5=21
f(3)=3²+6(3)+5=9+18+5=32

so the slope from (2,21) to (3,32) is (32-21)/(3-2)=11/1=11

answer is 11