Answer:
Please see the attached images for full solution.
For question 3, the equation could have also been 3x°= 90°. However, I used ∠ sum of △ since I didnt want to assume that ∠ABC is a right angle.
Likewise for Q4, the polygon looks like a trapezium which means that the 2 horizontal lines are parallel and one could conclude that (3x +3)° +(2x +2)°= 180° (int. ∠s). But since it wasn't clearly indicated that they are parallel, I used the sum of interior angles to find x instead.
