The answer of the given equation is [tex]-13y^{2} -11y+7[/tex]
Step-by-step explanation:
The given equation can be written as,
[tex](-8y^{2}+6y-1) +(-8y^{2}+8y+1)-(-3y^{2}+9y-9)[/tex]
= [tex]-8y^{2} +6y-1-8y^{2}-8y -1+3y^{2}-9y+9[/tex]
[Taking same powered variables together we get,]
=[tex](-8y^{2}-8y^{2}+3y^{2}) +(6y-8y-9y)-1-1+9[/tex]
= [tex]-13y^{2} -11y+7[/tex]
Here the answer.
