140 - (а+25) = 40 340 + (190-х) = 400 100 - (х+25) = 52 280 - (х+40) = 80 60 х+180=420 5 * а+500=4500:5 252:36*х=560 103300: (х+297) = 25*2

140 - (а + 25) = 40;

- (а + 25) = 40 - 140;

а + 25 = 140 - 40;

а + 25 = 100;

а = 100 - 25;

а = 75.

340 + (190 - х) = 400;

190 - х = 400 - 340;

190 - х = 60;

- х = 60 - 190;

- х = - 130;

х = 130.

100 - (х + 25) = 52;

- (х + 25) = 52 - 100;

- (х + 25) = - 48;

х + 25 = 48;

х = 48 - 25;

х = 23.

280 - (х + 40) = 80;

- (х + 40) = 80 - 280;

- (х + 40) = - 200;

х + 40 = 200;

х = 200 - 40;

х = 160.

60 х + 180 = 420;

60 х = 420 - 180;

60 х = 240;

х = 240 / 60;

х = 4.

5 * а + 500 = 4500 : 5;

5 * а + 500 = 900;

5 * а = 900 - 500;

5 * а = 400;

а = 400 / 5;

а = 80.

252 : 36 * х = 560;

(252 : 36) * х = 560;

7 * х = 560;

х = 560 / 7;

х = 80.

103300 : (х + 297) = 25 * 2;

103300 : (х + 297) = 50;

103300 : 50 = х + 297;

х + 297 = 103300 : 50;

х + 297 = 2066;

х = 2066 / 297;

х = 6,96.

Ответ: 75; 130; 23; 160; 4; 80; 80; 6,96.