Problem
Given that \( f(x)=x+4 \) and \( g(x)=x^{2}-x \), find \( (f+g)(3) \), if it exists. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( (f+g)(3)=12 \) (Simplify your answer.) B. The value for \( (f+g)(3) \) does not exist.
Solution
Step 1 ：\( (f+g)(3) = f(3) + g(3) \)
Step 2 ：\( f(3) = 3 + 4 = 7 \) and \( g(3) = 3^2 - 3 = 6 \)
Step 3 ：\( (f+g)(3) = 7 + 6 = 13 \)
