a) 47/100 X - 14/100 X = 165/100
33X = 165
X = 5
Proba: 0,47 x 5 - 0,15 x 5 = 2,35 - 0,7 = 1,65
b) 4X - 1 = -1/3 x 3
4X - 1 = -1
4X = 0
X = 0
Proba: ( 4 x 0 - 1 ) : 3 = - 1 : 3 = - 1/3
c) 7X - 6X = 18
X = 18
Proba: 7/9 x 18 - 2/3 x 18 = 14 - 12 = 2
d) - 6 + 45X = -6
45X = -6 + 6
X = 0
Proba: - 3 ( 2 - 15 x 0 ) = -3 ( 2 - 0 ) = - 3 x 2 = - 6