67085-к: 90=59397 700·(83400: m)=420000 (n+10986)·50=589650

1)
67.085 - k : 90 = 59.397
- k : 90 = 59.397 - 67.085
- k : 90 = - 7.688
k : 90 = 7.688
k = 7.688 * 90
k = 691.920
проверка:
67.085 - 691.920 : 90 = 59.397
67.085 - 7.688 = 59.397
59.397 = 59.397

2)
700 * (83.400 : m) = 420.000
83.400 : m = 420.000 : 700
83.400 : m = 600
m = 83.400 : 600
m = 139
проверка:
700 * (83.400 : 139) = 420.000
700 * 600 = 420.000

3)
(n + 10.986) * 50 = 589.650
n + 10.986 = 589.650 : 50
n + 10.986 = 11.793
n = 11.793 - 10.986
n = 807
проверка:
(807 + 10.986) * 50 = 589.650
11.793 * 50 = 589.650
589.650 = 589.650