(16+х)3=81; 5(67-х)=90; х-(28+42)=17; (54-37)+х=62

Найдем корни уравнений.

1) (16 + х)  * 3 = 81;

16 + x = 81/3;

16 + x = 9 * 9/3;

16 + x = 9 * 3;

16 + x = 27;

x = 27 16;

x = 11.

2)  5 * (67 - х) = 90;

67 x = 90/5;

67 x = 50/5 + 40/5;

67 x = 10 + 8;

67 x = 18;

-x = 18 67;

x = 67 18;

x = 50 1;

x = 49.

3) х - (28 + 42) = 17;

x (60 + 10) = 17;

x 70 = 17;

x = 17 + 70;

x = 87.

4)  (54 - 37) + х = 62;

20 3 + x = 62;

17 + x = 62;

x = 62 17;

x = 50 5;

x = 45.