Move all terms to one side.
Factor \({y}^{2}-8y-9\).
Ask: Which two numbers add up to \(-8\) and multiply to \(-9\)?
Rewrite the expression using the above.
\[(y-9)(y+1)\]
Solve for \(y\).
Ask: When will \((y-9)(y+1)\) equal zero?
When \(y-9=0\) or \(y+1=0\)
Solve each of the 2 equations above.
\[y=9,-1\]
