80. 1) 43x + 72 = 502; 3) 19y 200 = 47; 81. 1) (x + 58) – 37 = 91; 3) 69 – (y – 28) = 13; 82. 1) 321 + (x + 13). = 450; 3) 204 - (x + 29) = 100; 83. 1) (x – 23) · 14 = 56; 3) 205 : (y - 27) = 41; 5) 89. (6 + 13) = 7120;
Ответ:
43х+72=502
43х=502-72
43х=430
Х=10
19у-200=47
19у=47+200
19у=247
У=13
(Х+58)-37=91
Х+58-37=91
Х=91+37-58
Х=70
69-(у-28)=13
69-у+28=13
-у=13-28-69
-у=-84
У=84
321+(х+13)=450
321+х+13=450
Х=450-13-321
Х=116
204-(х+29)=100
204-х-29=100
-х=100+29-204
-х=-75
Х=75
(х-23)*14=56
14х-322=56
14х=56+322
14х=378
Х=27
205:(у-27)=41
У-27=205:41
У-27=5
У=5+27
У=32
b=877
8b=7016
8b=7120-104
8b+104=7120
8(в+13)=7120