Подстановка условия
[src](sqrt(y) - 3)*(y + 3*sqrt(3) + 9) при y = 1/2
(sqrt(y) - 3)*(y + 3*sqrt(3) + 9)
$$\left(\sqrt{y} - 3\right) \left(y + 3 \sqrt{3} + 9\right)$$
(sqrt((1/2)) - 3)*((1/2) + 3*sqrt(3) + 9)
$$\left(\sqrt{(1/2)} - 3\right) \left((1/2) + 3 \sqrt{3} + 9\right)$$
(sqrt(1/2) - 3)*(1/2 + 3*sqrt(3) + 9)
$$\left(-3 + \sqrt{\frac{1}{2}}\right) \left(\frac{1}{2} + 3 \sqrt{3} + 9\right)$$
(-3 + sqrt(2)/2)*(19/2 + 3*sqrt(3))
$$\left(-3 + \frac{\sqrt{2}}{2}\right) \left(3 \sqrt{3} + \frac{19}{2}\right)$$