Final answer:
To solve for a, follow these steps: combine like terms, subtract 30° from both sides, combine like terms, subtract 80° from both sides, and divide by 2.
Step-by-step explanation:
To solve for a, we need to use the given equation:
25° + 55° + a + a = ?° + 30°
Combining like terms, we have:
25° + 55° + 2a = ?° + 30°
Next, we can subtract 30° from both sides:
25° + 55° + 2a - 30° = ?°
Now, we can combine the like terms on the left side:
80° + 2a = ?°
To solve for a, we need to isolate it. To do this, we can subtract 80° from both sides:
2a = ?° - 80°
Finally, we can divide both sides by 2:
a = (?° - 80°) / 2