Can someone help me with isosceles triangles???

Answer:
1) x = 75°
2) x = 180° - 2×40° = 180° - 80° = 100°
3) x = 180° - 2×73° = 180° - 146° = 34°
4) x = (180° - 122°) : 2 = 58° : 2 = 29°
5) x = 90° - (180° - 80°) : 2 = 90° - 100° : 2 = 90° - 50° = 40°