\[
f(x)=3 x^{3}+5 x^{2}+7 x+4
\]
Step 3 of 3 : Find $f(a+1)$.
Answer
\[
f(a+1)=
\]

Answer

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Answer

$\boxed{f(a+1) = 3a^3 + 14a^2 + 26a + 19}$

Steps

Step 1 ：$f(a+1) = 3(a+1)^3 + 5(a+1)^2 + 7(a+1) + 4$

Step 2 ：$f(a+1) = 3(a^3 + 3a^2 + 3a + 1) + 5(a^2 + 2a + 1) + 7(a + 1) + 4$

Step 3 ：$f(a+1) = 3a^3 + 9a^2 + 9a + 3 + 5a^2 + 10a + 5 + 7a + 7 + 4$

Step 4 ：$f(a+1) = 3a^3 + 14a^2 + 26a + 19$

Step 5 ：$\boxed{f(a+1) = 3a^3 + 14a^2 + 26a + 19}$