|Position 1: White to move|
If White can get his knight to the b3 square he can force at least a draw. Here, his passed pawn gives him winning chances.
1. Ne6+ Ke3
The other variations are 1... Ke4 2. Nc5+ (followed by Nb3) and 1... Kf3 2. Nd4+ (again followed by Nb3)
Forcing the Black king into a skewer.
Otherwise White plays 4. Nb3 stopping the pawn.
3. h7 a1=Q
4. h8=Q+ Ke4
|Position 2: White to move|
In any position the first variations to calculate are the most forcing ones: Threats, checks and captures. Here, the most forcing variation wins.
1. d7 Rd4
2. a7 Bf3
It seems that Black has stopped the pawns. But White has a hidden card to play.
3. Ng4+! Kh5
The bishop and rook are tied to watching the pawns: 3... Bxg4 4. a8=Q and 3... Rxg4 4. d8=Q both lose for Black.
4. Nf6+ Kxh4
A deadly interference tactic. Whichever piece captures the knight gets in the way of the other piece.
Or 5... Bxd5 6. d8=Q+
All the best for your remaining exams!