9514 1404 393
Answer:
y = 0
Step-by-step explanation:
Subtracting the right side gives ...
[tex]\dfrac{y}{P-9}-\dfrac{y}{P+9}=0\\\\y\left(\dfrac{(P+9)-(P-9)}{P^2-81}\right)=0\\\\y\left(\dfrac{18}{P^2-81}\right)=0\\\\\boxed{y=0}[/tex]
The factor multiplying y cannot be zero, so y must be zero.