c) (25 - 6x) . 3 - 5 = 7
(25 - 6x) . 3=7+5
(25 - 6x) . 3=12
25 - 6x=12/3
25 - 6x=4
6x=25-4
6x=21
x=21/6
x=3,5
a) (3x - 23) . 14 = 98
(3x - 23)=98/14
3x-23=7
3x=7+23
3x=30
x=30/3
x=10
b) (4x + 5) : 3 = 7
(4x + 5)=7.3
4x +5 =21
4x=21-5
4x=16
x=16/4
x=4
d) 180 : (x + 2) - 12 = 33
180 : (x + 2)=33+12
180 : (x + 2)=45
(x + 2)=180/45
x + 2=4
x=4-2
x=2