Вопрос по математике:

10-9y=70-6y 10z+7=9z+5 25-12m=45-8m -9x-56=5x 17-8y=4y-7 5y+15=4y+20

10 - 9y = 70 - 6y;

- 9у + 6у = 70 - 10;

- 3у = 60;

- у = 60 : 3;

- у = 20;

у = - 20;

10 - 9 * (- 20) = 70 - 6 * (- 20);

10 + 180 = 70 + 120;

190 = 190;

10z + 7 = 9z + 5;

10z - 9z = 5 - 7;

z = - 2;

10 * (-2) + 7 = 9 * (-2) + 5;

- 20 + 7 = - 18 + 5;

- 13 = - 13;

25 - 12m = 45 - 8m;

- 12m + 8m = 45 - 25;

- 4m = 20;

- m = 20 : 4;

- m = 5;

m = - 5;

25 - 12 * (- 5) = 45 - 8 * (- 5);

25 + 60 = 45 + 40;

85 = 85;

- 9x - 56 = 5x;

- 9х - 5х = 56;

- 14х = 56;

- х = 56 : 14;

- х = 4;

х = - 4;

- 9 * (- 4) - 56 = 5 * (- 4);

36 - 56 = - 20;

- 20 = - 20;

17 - 8y = 4y - 7;

- 8у - 4у = - 7 - 17;

- 12у = - 24;

- у = - 24 : 12;

- у = - 2;

у = 2;

17 - 8 * 2 = 4 * 2 - 7;

17 - 16 = 8 - 7;

1 = 1;

5y + 15 = 4y + 20;

5у - 4у = 20 - 15;

у = 5;

5 * 5 + 15 = 4 * 5 + 20;

25 + 15 = 20 + 20;

40 = 40.