Answer:
[tex]f(3+h) = h^2 +9h + 23[/tex]
Step-by-step explanation:
[tex]\text{Given that,}\\\\f(x) = x^2 +3x +5\\\\f(3+h) = (3+h)^2 +3(3+h) + 5\\\\~~~~~~~~~~~~=3^2 +2\cdot 3 \cdot h + h^2 +9+3h +5\\\\~~~~~~~~~~~~=9+ 6h +h^2 +14+3h\\\\~~~~~~~~~~~~=h^2 +9h + 23[/tex]