y =-1
Last option is correct.
Step-by-step explanation:
The given equation is ![9+y=8](/tpl/images/0329/8556/73f12.png)
In order to solve for y, we need to isolate y.
In this equation 9 is added with y and hence in order to eliminate 9 from the left hand side, we do reverse operation of addition.
The reverse operation of addition is subtraction. Hence, we subtract 9 to both sides of the equation
![9+y-9=8-9](/tpl/images/0329/8556/e21ed.png)
On simplifying, we get
![y=-1](/tpl/images/0329/8556/0c337.png)
Hence, value of y is -1
Last option is correct.