Решите уравнение 1) (40+x)*10=800 2) (x-56)*9=909 3) x+x+100=28028/14 4( 3x+4x+700=70*16

1) (40 + x) * 10 = 800; 

Найдем х.

40 + x = 800/10;

40 + x = 80;

x = 80 - 40;

x = 40.

2) (x - 56) * 9 = 909; 

x - 56 = 909/9;

x - 56 = 100 + 1;

x = 100 + 1 + 56;

x = 100 + 57;

x = 157.

3) x + x + 100 = 28 028/14; 

x + x + 100 = 2 002;

2 * x + 100 = 2 002;

2 * x = 2 002 - 100;

2 * x = 1 902;

x = 1 902/2;

x = 951.

4) 3 * x + 4 * x + 700 = 70 * 16; 

3 * x + 4 * x + 700 = 1 120; 

7 * x + 700 = 1 120; 

7 * x = 1 120 - 700; 

7 * x = 420; 

x = 420/7; 

x = 60.