Answer:
B. 2x + 40 = 180
Step-by-step explanation:
The angles GHI and KHI form a straight line. It means that the sum of them is equal to 180. So, we can write the following equation:

Now, we can replace ∠GHI = x + 30 and ∠KHI = x + 10 to get:

Therefore, the answer is:
B. 2x + 40 = 180