3x° is a right angle so it equals 90°. To solve for x, you need to divide 90 by 3. This equals 30.
In order to find what the angle with y equals, you have to find the rest of them. So if you add 135° + 90° + 90° you get 215. Which is the missing angle.
So to solve for y in (5y - 5) = 45°, you add 5 to 45, which is 50 and then divide by 5. This is how you get y=10.
