Jawabanmu

2014-05-29T18:52:53+07:00
(81x2):18=162:18=9

2X+3=9
2X+3-3=9-3
2X=6
X=3

Maaf kalo salah :)
2014-05-29T18:54:16+07:00
L = d x d
         2
81 = 18 x (2X + 3)
               2
2X + 3 = 81
              9
2X + 3 = 9
2X = 9 - 3
2X = 6
X = 6  = 3 cm
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