Answer: f(3)=11.5
Explanation:
In order to solve this equation, all you have to substitute the value inside of the parenthesis with the value of x in the equation after the equals sign. SO...
f(3)=3x+2.5
f(3)=3(3)+2.5
f(3)=9+2.5
f(3)=11.5
Hope this helps!