1) 15c + 3c - 12 = 78;
15c + 3c = 78 + 12;
18c = 90;
c = 5;
2) (6y + 14): 2 = 40 - 15;
6y + 14 = 25 * 2;
6y + 14 = 50;
6y = 50 - 14 ;
6y = 36;
y = 6.
1) 15c + 3c - 12 = 78;
15c + 3c = 78 + 12;
18c = 90;
c = 5;
2) (6y + 14): 2 = 40 - 15;
6y + 14 = 25 * 2;
6y + 14 = 50;
6y = 50 - 14 ;
6y = 36;
y = 6.