Решите уравнение: а)3х+7х+18=178; б)6у-2у+25=65; в)7z+6z-13=130; г)21t-4t-17=17

а) 3х + 7х + 18 = 178;

10х + 18 = 178;

10х = 178 - 18;

10х = 160;

х = 160 : 10;

х = 16;

3 * 16 + 7 * 16 + 18 = 178;

48 + 112 + 18 = 178;

160 + 18 = 178;

178 = 178.

б) 6у - 2у + 25 = 65;

4у + 25 = 65;

4у = 65 - 25;

4у = 40;

у = 40 : 4;

у = 10;

6 * 10 - 2 * 10 + 25 = 65;

60 - 20 + 25 = 65;

40 + 25 = 65;

65 = 65.

в) 7z + 6z - 13 = 130;

13z - 13 = 130;

13z = 130 + 13;

13z = 143;

z = 143 : 13;

z = 11;

7 * 11 + 6 * 11 - 13 = 130;

77 + 66 - 13 = 130;

143 - 13 = 130;

130 = 130.

г) 21t - 4t - 17 = 17;

17t - 17 = 17;

17t = 17 + 17;

17t = 34;

t = 34 : 17;

t = 2;

21 * 2 - 4 * 2 - 17 = 17;

42 - 8 - 17 = 17;

34 - 17 = 17;

17 = 17.