The missing values for the missing angles are:
1) x = 12
2) x = 11
3) x = 4
How to find the missing angle?
We know that the exterior angle theorem asserts that if a triangle's side gets extended, then the resultant exterior angle will be equal to the total of the two opposite interior angles of the triangle.
Thus:
1) 30 + 4x + 2 = 8 + 6x
6x - 4x = 24
2x = 24
x = 12
2) 5x + 10 + 58 = 11x + 2
6x = 66
x = 11
3) 46 + 8x - 1 = 18x + 5
10x = 40
x = 4