3X12=36 IN THIS ADD THE FIRST NUMBER OF SEQUENCE , 36+3=39,
3X21=63 IN THIS ADD THE SECOND NUMBER OF SEQUENCE, 63+12=75,
3x39=117 in this add the third number of sequence, 117+ 21=138,
3x75=225 in this add second number of sequence, remember now the pattern of multiplication is reversing
so 225+12=237
3x237=711 in this add first number of sequence, remember the sequence for pattern of multiolication is reversing so 711+3=714.........
714 is the answer .............now u r happy