((1(целая) 2\5)-1,6):0,12= 3(целых) 1\2 * (2\3х +4\7) 3\5z+2\3z=3(целых) 4\5

1) ((1 2/5) - 1,6) : 0,12 = 3 1/2 * (2/3 * х + 4/7);

((1 * 5 + 2)/5) - 1,6) : 12/100 = (3 * 2 + 1)/2 * (2/3 * х + 4/7);

(7/5 - 16/10) * 100/12 = 7/2 * (2/3 * х + 4/7);

(14/10 - 16/10) * 100/12 = 7/2 * 2/3 * х + 7/2 * 4/7;

 - 2/10 * 100/12 = 7/3 * х + (7 * 4)/(2 * 7);

 - 5/3 = 7/3 * х + 2;

 7/3 * х = -5/3 - 6/3;

х = (-5 - 6)/3 * 3/7 = (-11 * 3)/(3 * 7) = -11/7.

Ответ: х = -11/7.

2) 3/5 * z + 2/3 * z = (3 * 5 + 4)/5;

(3/5 + 2/3) * z = 19/5;

(9/15 + 10/15) * z = 19/5;

(9 + 10)/15 * z = 19/5;

z = 19/5 : 19/15 = 19/5 * 15/19 = (19 * 15)/(5 * 19) = 15/5 = 3.

Ответ: z = 3.