A :12 du 1
A : 8 = X du 12
A :12 =Y du 1
X * 8 +12= Y *12 +1 ﴾dau * la dau nhan nha ﴿
X+13=Y
﴾ X+13﴿*8+12=Y*12 +1
X * 8 +104 +12 = Y *12 +1
X*12 ‐ y x8=116 ‐8
X* 4 =108
X = 108 :4
X = 27
vay so do la
: 27 * 8 + 5 =221
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