8.5-5/8*2.4/(7/15-5/18)*2 11/17=(2 3/22-2/55)*0.6/0.45x

8.5 - 5/8 * 2.4 / (7/15 - 5/18) * 2 11/17 = (2 3/22 - 2/55) * 0.6 / 0.45x;

8.5 - 5/8 * 2.4 / (7 * 6 - 5 * 5)/90 * 2 11/17 = (47/22 - 2/55) * 0.6 / 0.45x;

8.5 - 5/8 * 2 4/10 / (42 - 25)/90 * 45/17 = (47 * 5 - 2 * 2)/110 * 0.6 / 0.45x;

8.5 - 5/8 * 24/10 / 17/90 * 45/17 = (235 - 4)/110 * 0.6 / 0.45x;

8.5 - 5/8 * 12/5 / 1/2 = 231/110 * 6/10 / 0.45x;

8.5 - 1/2 * 3 * 2/1 = 231/55 * 3/10 / 45/100 x;

8.5 - 3 = 231/55 * 3/10 * 100/45 x;

5.5 = 231/55 * 2/3 x;

5.5 = 154/55 x;

5 5/10 = 154/55 х;

55/10 = 154/55 х;

11/2 = 154/55 х;

х = 11/2 : 154/55;

х = 11/2 * 55/154;

х = 605/308;

х = 1 297/308.

Ответ:  1 297/308.