I'm unable to directly analyze the images, but I can help you understand the concepts related to geometry and the questions from your assignment based on the given descriptions.

For **Hình 31**:
- **Part a** asks you to prove that the lines \( x \) and \( y \) are parallel. Given the angle of \( 130^\circ \) between line \( x \) and the transversal \( MN \), you can use the properties of alternate interior angles or same-side interior angles to show that \( x \parallel y \).

- **Part b** asks for the value of \( N_1 \). If \( N_1 \) represents the angle formed at point \( N \), you could find it by using the property that angles on a straight line sum up to \( 180^\circ \). If \( 130^\circ \) is given, then \( N_1 \) can be calculated as \( N_1 = 180^\circ - 130^\circ \).

For **Hình 32**:
- **Part a** likely asks you to calculate \( B_1 \) in a similar way by considering the angles created at the intersection of the lines.

- **Part b** indicates the necessity to state the parallelism involving lines \( y \) and \( x \). You would then apply a similar reasoning to prove that since \( y \) and \( x \) are cut by transversal line \( BD \), they either confirm or deny their parallelism based on the angles given.

If you have any specific questions or need more explanation on any part, feel free to ask!