Решите уравнение:
а) 14x − 9x = 125;
б) 13x + 5x = 108 : 2;
в) 15y + 25y = 120;
г) 29y − 17y = 12 * 4.
14x − 9x = 125
5x = 125
x = 125 : 5
x = 25
13x + 5x = 108 : 2
18x = 54
x = 54 : 18
x = 3
15y + 25y = 120
40y = 120
y = 120 : 40
y = 3
29y − 17y = 12 * 4
12y = 48
y = 48 : 12
y = 4