Answer:
[tex]y^{2} - 64[/tex]
Step-by-step explanation:
[tex]\frac{y+8}{y^{2} + 7 } = \frac{k}{(y^{2} + 7) (y-8) }[/tex]
This gives x= [tex]y^{2} - 64[/tex]
Using the formula that [tex]x^{2} - y^{2} = (x+y)(x-y)[/tex]