bonsoir
AE = 19 - 9 = 10
x = 10 * 1/4 = 10/4 = 5/2
3 x + 52 = 180
3 x = 180 - 52
3 x = 128
x = 42.6°
2 x + 1 = 13
2 x = 13 - 1
2 x = 12
x = 6
14 = 20 - 3 x
14 - 20 = - 3 x
- 6 = - 3 x
x = - 6/-3 = 2
2 x + 1/7 = 1
2 x = 1 - 1/7
2 x = 7/7 - 1/7
2 x = 6/7
14 x /7 = 6/7
14 x = 6
x = 6/14 = 3/7
continues