The perfect square
Let's highlight the perfect square of the square three-member
$$\left(- 9 p^{2} - 5 p\right) - 4$$
To do this, let's use the formula
$$a p^{2} + b p + c = a \left(m + p\right)^{2} + n$$
where
$$m = \frac{b}{2 a}$$
$$n = \frac{4 a c - b^{2}}{4 a}$$
In this case
$$a = -9$$
$$b = -5$$
$$c = -4$$
Then
$$m = \frac{5}{18}$$
$$n = - \frac{119}{36}$$
So,
$$- 9 \left(p + \frac{5}{18}\right)^{2} - \frac{119}{36}$$
/ _____\ / _____\
| 5 I*\/ 119 | | 5 I*\/ 119 |
|p + -- + ---------|*|p + -- - ---------|
\ 18 18 / \ 18 18 /
$$\left(p + \left(\frac{5}{18} - \frac{\sqrt{119} i}{18}\right)\right) \left(p + \left(\frac{5}{18} + \frac{\sqrt{119} i}{18}\right)\right)$$
(p + 5/18 + i*sqrt(119)/18)*(p + 5/18 - i*sqrt(119)/18)
General simplification
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$$- 9 p^{2} - 5 p - 4$$
Combining rational expressions
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$$p \left(- 9 p - 5\right) - 4$$
Assemble expression
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$$- 9 p^{2} - 5 p - 4$$
Rational denominator
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$$- 9 p^{2} - 5 p - 4$$