решите уравнения 19 + (12+7a+8a) = 76 2) 54: (x-7) + 22=31 3) (29-x) * 2-7=45 4) 3 * (x+4) - 12=24 5) 45: (17-x) + 9=24

1) 19 + (12 + 15 а) = 76;

12 + 15 а = 76 - 19;

12 + 15 а = 57;

15 а = 57 - 12;

15 а = 45;

а = 45 : 15 = 3.

2) 54 : (х - 7) + 22 = 31;

54 : (х - 7) = 31 - 22;

54 = 9

х - 7 1;

9 х - 63 = 54;

9 х = 54 + 63;

9 х = 117;

х = 117 : 9 = 13.

3) (29 - х) * 2 - 7 = 45;

58 - 2 х - 7 = 45;

2 х = 58 - 7 - 45;

2 х = 6;

х = 3.

4) 3 * (х + 4) - 12 = 24;

3 х + 12 - 12 = 24;

3 х = 24;

х = 24 : 3 = 8.

5) 45 : (17 - х) + 9 = 24;

45 = 24 - 9;

17 - х

45 = 15

17 - х 1;

15 * (17 - х) = 45

255 - 15 х = 45;

15 х = 255 - 45;

15 х = 210;

х = 210 : 15 = 14.