[(a+116:2)*3]*11=1991
( a + 58 ) · 3 = 1991 :11
( a + 58) · 3 = 181
a + 58 = 181 :3
a= 181 / 3 -58
a = ( 181 - 58· 3) / 3 = (181 - 174) / 3 = 7 /3
(b:11-4):3-110:2=4
( b :11 - 4) :3 - 55 = 4
( b : 11 - 4) :3 = 55 + 4
b : 11 - 4 = 59 · 3
b :11 = 177 + 4
b = 11 ·181 = 1991
