(12 5/13+y)-9 9/15=7 7/13
y= 7 7/13-12 5/13+9 9/15
y= -4 11/13+ 9 9/15
y= - 63/13 +144/15
y= (-945+1872)/195
y= 927/195= 309/65= 4 49/65
