21+124 569:9-2×a-107 = 6 737
21+124 569:9-2×a = 6 737+107
124 569:9-2×a = 6 844-21
13 841-2×a = 6 823
2×a = 13 841-6 823
2×a = 7 018 |:2
a = 3 509
(18×b-1 278):149=36
18×b-1 278 = 36×149
18×b = 5 364+1 278
18×b = 6 642 |:18
b = 369
[(a+41+56):2-20]:10 = 3
(a+97):2-20 =3×10
(a+97):2 = 30+20
a+97 = 50×2
a = 100-97
a = 3
