Răspuns :
[(s*2*2)-5-5-5-5-5] *18=3438
[(s*2*2)-25]=3438:18=191
s*2*2=191+25=216
s*4=216
s=216:4=54
[(s*2*2)-25]=3438:18=191
s*2*2=191+25=216
s*4=216
s=216:4=54
[(a×2×2)-5-5-5-5-5]×18=3 438/:18
(a×2×2)-25=191/+25
a×2×2=216
a×4=216
a=216:4
a=54
(a×2×2)-25=191/+25
a×2×2=216
a×4=216
a=216:4
a=54