Supplementary angles are two angles whose measures add up to 180 degrees. We are given:
- Measure of angle F = 77 degrees
- Measure of angle H = (5x + 18) degrees
To find the equation to determine the value of \( x \), we can set up the following equation based on the definition of supplementary angles:
\[ 77 + (5x + 18) = 180 \]
This equation states that the sum of the measure of angle F and the measure of angle H is equal to 180 degrees.
Now we can simplify this:
- Combine like terms:
\[ 77 + 5x + 18 = 180 \]
- Add 77 and 18 together:
\[ 95 + 5x = 180 \]
Thus, the equation we want to use to find the value of \( x \) is:
\[ 77 + (5x + 18) = 180 \]
So, the correct answer is B:
\[ \text{B. } 77 + (5x + 18) = 180 \]