Only answer if your sure, 3y-y+2y-5=7-2y+5, what is y?

The first thing you need to do is combine like terms. 

3y-y+2y-5 = 7-2y + 5     (Subtract y)
2y + 2y -5 = 7-2y + 5     (Add 2y)
4y - 5 = 7-2y + 5            (add 5 and 7)
4y - 5 = 12-2y                 (add 2y to both sides)
6y - 5 = 12                      (add 5 to both sides)
6y = 14                            (divide by 6 on both sides)
y = 2.833333                 (Simplify)
y = 2.83