To complete the square for the polynomial \(y^2 + 22y\), we need to add a specific number that makes it a perfect-square quadratic.
- Take the coefficient of \(y\), which is 22.
- Divide it by 2 to get 11.
- Square that result: \(11^2 = 121\).
Now, we can rewrite the expression by adding \(121\): \[ y^2 + 22y + 121 \]
So, the number that makes the polynomial a perfect-square quadratic is 121.
The completed square form of the polynomial is: \[ (y + 11)^2 \]