Answer:

16.5

You just need to substitute it :

f(x) = 6x+1.5

→ f (2.5) = 6x + 1.5

→ f (2.5) = 6(2.5) + 1.5

→ f (2.5) = 15 + 1.5

→ f (2.5) = 16.5

Step-by-step explanation:

hope it helps