The perfect square
Let's highlight the perfect square of the square three-member
$$- 4 x^{2} + \left(- x 13 y - y^{2}\right)$$
Let us write down the identical expression
$$- 4 x^{2} + \left(- x 13 y - y^{2}\right) = \frac{153 y^{2}}{16} + \left(- 4 x^{2} - 13 x y - \frac{169 y^{2}}{16}\right)$$
or
$$- 4 x^{2} + \left(- x 13 y - y^{2}\right) = \frac{153 y^{2}}{16} - \left(2 x + \frac{13 y}{4}\right)^{2}$$
General simplification
[src]
$$- 4 x^{2} - 13 x y - y^{2}$$
/ / ____\\ / / ____\\
| y*\-13 + 3*\/ 17 /| | y*\13 + 3*\/ 17 /|
|x - ------------------|*|x + -----------------|
\ 8 / \ 8 /
$$\left(x - \frac{y \left(-13 + 3 \sqrt{17}\right)}{8}\right) \left(x + \frac{y \left(3 \sqrt{17} + 13\right)}{8}\right)$$
(x - y*(-13 + 3*sqrt(17))/8)*(x + y*(13 + 3*sqrt(17))/8)
Assemble expression
[src]
$$- 4 x^{2} - 13 x y - y^{2}$$
$$- 4 x^{2} - 13 x y - y^{2}$$
$$- 4 x^{2} - 13 x y - y^{2}$$
-y^2 - 4.0*x^2 - 13.0*x*y
-y^2 - 4.0*x^2 - 13.0*x*y
Combining rational expressions
[src]
$$- 4 x^{2} + y \left(- 13 x - y\right)$$
$$- 4 x^{2} - 13 x y - y^{2}$$
Rational denominator
[src]
$$- 4 x^{2} - 13 x y - y^{2}$$
$$- 4 x^{2} - 13 x y - y^{2}$$