3x - (10-9x) = 2 (x-2) 3 (x+5) = 7-5x 19 (y-9) = 3 (y+7) решить

1) 3 * x - (10 - 9 * x) = 2 * (x - 2);

3 * x - 10 + 9 * x = 2 * x - 2 * 2;

3 * x + 9 * x - 2 * х = 10 - 4;

(3 + 9 - 2) / * х = 6;

10 * х = 6;

х = 6/10 = 0,6;

2) 3 * (x + 5) = 7 - 5 * x;

3 * x + 3 * 5 = 7 - 5 * x;

3 * х + 5 * х = 7 - 15;

(3 + 5) * х = - 8;

х = - 8/8 = - 1;

3) 19 * (y - 9) = 3 * (y + 7);

19 * y - 9 * 19 = 3 * y + 7 * 3;

19 * y - 171 = 3 * y + 21;

19 * у - 3 * у = 21 + 171;

16 * у = 192;

у = 192/16 = 12.