[( a + 260:2) × 3] + 5 - 12 = 1997
[( a + 130 ) × 3 ] + 5 = 1997 + 12
[( a + 130 ) × 3 ] + 5 = 2009 / -5
[( a + 130 ) × 3 ] = 2004
( a + 130 ) = 2004 : 3
a + 130 = 668
a = 668 - 130
a = 538
