352 : c = 12 rest 4
c = ( 352 - 4 ) : 12
c = 348 : 12
c = 29
20 : d × 35 = 700
20 : d = 700 : 35
20 : d = 20
d = 20 : 20
d = 1
1706 + f × 13 = 2031
f × 13 = 2031 - 1706
f × 13 = 325
f = 325 : 13
f = 25
X : 13 × 9 = 819
X : 13 = 819 : 9
X : 13 = 91
X = 91 × 13
X = 1183