Найти x из пропорции
2:3=(5x-7):12

2:3 = (5x - 7):12;

5x - 7 = (2*12) : 3;

5x - 7 = 2 * 4;

5x - 7 = 8;

5x = 8 + 7;

5x = 15;

x = 15 : 5;

x = 3;