Answer:
x = 13
Explanation:
Add 3x and 4x - 1 together to get 7x-1. Since the angle on the bottom right is 90 degrees, we can safely assume that the remaining angles add up to 90 degrees. Add 1 on both sides to get 7x = 91. Divide 7 on both sides to get 13 as your x value.
To plug in the x value, plug 13 in. The one on the bottom left should equal to 39 degrees and the one on the top right should equal to 51 degrees.