The perfect square
Let's highlight the perfect square of the square three-member
$$\left(- y^{2} - y\right) + 4$$
To do this, let's use the formula
$$a y^{2} + b y + c = a \left(m + y\right)^{2} + n$$
where
$$m = \frac{b}{2 a}$$
$$n = \frac{4 a c - b^{2}}{4 a}$$
In this case
$$a = -1$$
$$b = -1$$
$$c = 4$$
Then
$$m = \frac{1}{2}$$
$$n = \frac{17}{4}$$
So,
$$\frac{17}{4} - \left(y + \frac{1}{2}\right)^{2}$$
/ ____\ / ____\
| 1 \/ 17 | | 1 \/ 17 |
|x + - - ------|*|x + - + ------|
\ 2 2 / \ 2 2 /
$$\left(x + \left(\frac{1}{2} - \frac{\sqrt{17}}{2}\right)\right) \left(x + \left(\frac{1}{2} + \frac{\sqrt{17}}{2}\right)\right)$$
(x + 1/2 - sqrt(17)/2)*(x + 1/2 + sqrt(17)/2)