Since angles $F$ and $H$ are supplementary, their measures add up to 180°. Therefore, the correct equation to find $x$ is:

$77 + (5x + 18) = 180$

So, the answer is B. $77 + (5x + 18) = 180$.

Would you like a detailed solution for solving $x$ in this equation, or do you have any other questions?

Here are 5 related questions for practice:

1. What is the value of $x$ in this equation?
2. How can we verify that angles are supplementary?
3. If $\angle F = 60^\circ$, what would $\angle H$ be in terms of $x$?
4. What does it mean for two angles to be complementary, and how would that equation differ?
5. What are other types of angle relationships that form equations like this?

Tip: Always check that the sum of angles satisfies the relationship stated (e.g., 180° for supplementary angles).