Answer:
x = 13, angle = 37
Step-by-step explanation:
The full angle will be a right angle, so 90 degrees.
You are given 53, on one side, so you just need to find the other bit.
Here, you can do 90 - 53 and get 37, which has to be equal to your unknown angle.
2x + 11 = 37
2x = 26
x = 13
