Решите уравнения 56+490/c=63 (d*80) / 2=240 560 / (13-d) + 20=100

1) 56+490/с=63 2) (d*80) / 2=240 3) 560 / (13-d) + 20=100

490/с=63-56 d*800=240*2 560 / (13-d) = 100-20

490/с=7 d*8=480 560 / (13-d) = 80

с=490/7 d=480/8 13-d = 560/80

с=70 d=60 13-d=7

d=13-7

d=6